The atmospheric circulation response to the global warming-like tropical upper tropospheric heating is revisited using a dry atmospheric general circulation model (AGCM) in light of a new diagnostics based on the concept of finite-amplitude wave activity (FAWA) on equivalent latitude. For a given tropical heating profile, the linear Wentzel-Kramers-Brillouin (WKB) wave refraction analysis sometimes gives a very different and even opposite prediction of the eddy momentum flux response to that of the actual full model simulation, exposing the limitation of the traditional linear approach in understanding the full dynamics of the atmospheric response under global warming. The implementation of the FAWA diagnostics reveals that in response to the upper tropospheric heating, effective diffusivity, a measure of the mixing efficiency, increases and advances upward and poleward in the subtropics and the resultant enhancement and the poleward encroachment of eddy potential vorticity mixing leads to a poleward displaced potential vorticity (PV) gradient peak in the upper troposphere. The anomalous eddy PV flux, in balance with the PV dissipation, gives rise to a poleward shift in the eddy-driven jet and eddy-driven mean meridional circulation. Sensitivity experiments show that these irreversible dissipation processes in the upper troposphere are robust, regardless of the width of the tropical heating.

Solar PV Energy 101: Solar PV Addthis Description Solar photovoltaic (PV) systems can generate clean, cost-effective power anywhere the sun shines. This video shows how a PV panel converts the energy of the sun into renewable electricity to power homes and businesses. Text Version Below is the text version for the Energy 101: Solar PV video. The video opens with "Energy 101: Solar PV." This is followed by a timelapse shot of a city skyline as day turns to night. All right, we all know

This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions. Each function in the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.

A supported PV assembly may include a PV module comprising a PV panel and PV module supports including module supports having a support surface supporting the module, a module registration member engaging the PV module to properly position the PV module on the module support, and a mounting element. In some embodiments the PV module registration members engage only the external surfaces of the PV modules at the corners. In some embodiments the assembly includes a wind deflector with ballast secured to a least one of the PV module supports and the wind deflector. An array of the assemblies can be secured to one another at their corners to prevent horizontal separation of the adjacent corners while permitting the PV modules to flex relative to one another so to permit the array of PV modules to follow a contour of the support surface.

Solar photovoltaic (PV) systems can generate clean, cost-effective power anywhere the sun shines. This video shows how a PV panel converts the energy of the sun into renewable electricity to power homes and businesses.

Solar photovoltaic (PV) systems can generate clean, cost-effective power anywhere the sun shines. This video shows how a PV panel converts the energy of the sun into renewable electricity to power homes and businesses.

A stabilized PV system comprises an array of photovoltaic (PV) assemblies mounted to a support surface. Each PV assembly comprises a PV module and a support assembly securing the PV module to a position overlying the support surface. The array of modules is circumscribed by a continuous, belt-like perimeter assembly. Cross strapping, extending above, below or through the array, or some combination of above, below and through the array, secures a first position along the perimeter assembly to at least a second position along the perimeter assembly thereby stabilizing the array against wind uplift forces. The first and second positions may be on opposite sides on the array.

This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functio ns are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in th e OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions. Each function i n the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.

A fire resistant PV shingle assembly includes a PV assembly, including PV body, a fire shield and a connection member connecting the fire shield below the PV body, and a support and inter-engagement assembly. The support and inter-engagement assembly is mounted to the PV assembly and comprises a vertical support element, supporting the PV assembly above a support surface, an upper interlock element, positioned towards the upper PV edge, and a lower interlock element, positioned towards the lower PV edge. The upper interlock element of one PV shingle assembly is inter-engageable with the lower interlock element of an adjacent PV shingle assembly. In some embodiments the PV shingle assembly may comprise a ventilation path below the PV body. The PV body may be slidably mounted to the connection member to facilitate removal of the PV body.

A method is described for providing solar irradiance data for modeling PV performance by using measured PV performance data and back-solving for the unknown direct normal irradiance (DNI) and diffuse horizontal irradiance (DHI), which can then be used to model the performance of PV systems of any size, PV array tilt, or PV array azimuth orientation. Ideally situated for using the performance data from PV modules with micro-inverters, the PV module operating current is used to determine the global tilted irradiance (GTI), and a separation model is then used to determine the DNI and DHI from the GTI.

PV ValueÂź is a free solar PV Valuation tool that answers the question of "How much is solar PV worth" and is compliant with the Uniform Standards of Professional Appraisal Practice. It is available for and being used by real estate appraisers, realtors, homeowners, commercial building owners, home builders, solar installers, green raters, insurance companies, and mortgage lenders in all 50 states along with D.C. and Puerto Rico. PV ValueÂź allows for the calculation of both the cost and income approach to value and was endorsed by the largest appraiser trade organization, the "Appraisal Institute," as an innovative approach to valuing solar assets.

While an organized source of reference information on PV performance modeling is certainly valuable, there is nothing to match the availability of actual examples of modeling algorithms being used in practice. To meet this need, Sandia has developed a PV performance modeling toolbox (PV_LIB) for Matlab. It contains a set of well-documented, open source functions and example scripts showing the functions being used in practical examples. This toolbox is meant to help make the multi-stepmoreÂ Â» process of modeling a PV system more transparent and provide the means for model users to validate and understand the models they use and or develop. It is fully integrated into MatlabÂs help and documentation utilities. The PV_LIB Toolbox provides more than 30 functions that are sorted into four categoriesÂ«Â less

Matlab Toolbox for simulating the impact of solar energy on the distribution grid. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving GridPV Toolbox information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feedermoreÂ Â» on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions.Â«Â less

Matlab Toolbox for simulating the impact of solar energy on the distribution grid. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving GridPV Toolbox information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions.

Atmospheric conditions at the site of a cosmic ray observatory must be known for reconstructing observed extensive air showers. The Global Data Assimilation System (GDAS) is a global atmospheric model predicated on meteorological measurements and numerical weather predictions. GDAS provides altitude-dependent profiles of the main state variables of the atmosphere like temperature, pressure, and humidity. The original data and their application to the air shower reconstruction of the Pierre Auger Observatory are described. By comparisons with radiosonde and weather station measurements obtained on-site in Malargue and averaged monthly models, the utility of the GDAS data is shown.

PV Value PV Value PV Value Sandia National Laboratories has developed a prospective model of determining the value of PV. Sandia uses an income capitalization approach, which considers the present value of future energy production to determine the remaining value of a PV system. An online tool developed by Energy Sense Finance, has been released to the public. https://www.pvvalue.com/ PV Value (332.15 KB) More Documents & Publications PV ValueÂź Reduce Risk, Increase Clean Energy: How States

This brochure summarizes the Open PV Project, a collaborative effort of government, industry, and the public to compile a comprehensive database of PV installations in the United States. The brochure outlines the purpose and history of the project as well as the main capabilities and benefits of the online Open PV tool. The brochure also introduces how features of the tool are used, and it describes the sources and characteristics of Open PV's data and data collection processes.

Through Ukiah Utilitiesâ PV Buydown Program, residential and commercial customers are eligible for a $1.40-per-watt AC rebate on qualifying grid-connected PV systems up to a maximum system size of...

A common misconception about solar photovoltaic (PV) panels is that they inherently cause or create "too much" glare, posing a nuisance to neighbors and a safety risk for pilots. While solar PV systems can produce glare, light absorption - rather than reflection - is central to the function of solar PV panels. This fact sheet describes the basic issues surrounding glare from solar PV panels, the new Federal Aviation Administration guidance, and the implications for local governments.

The National Renewable Energy Laboratory hosts an annual Photovoltaic (PV) Module Reliability Workshop so that solar technology experts can share information leading to the improvement of PV module reliability. Improvements to module reliability reduce the cost of solar electricity and promotes investor confidence in the technologyâboth critical goals for moving PV technologies deeper into the electricity marketplace.

The DOE SUNSHOT workshop is seeking input from the community about PV reliability and how the DOE might address gaps in understanding. This presentation describes the types of testing that are needed for PV reliability and introduces a discussion to identify gaps in our understanding of PV reliability testing.

This software requires inputs of simple general building characteristics and usage information to calculate the energy and cost benefits of solar PV. This tool conducts and complex hourly simulation of solar PV based primarily on the area available on the rooftop. It uses a simplified efficiency calculation method and real panel characteristics. It includes a detailed rate structure to account for time-of-use rates, on-peak and off-peak pricing, and multiple rate seasons. This tool includes themoreÂ Â» option for advanced system design inputs if they are known. This tool calculates energy savings, demand reduction, cost savings, incentives and building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.Â«Â less

A photovoltaic (PV) device, comprising a PV interband cascade (IC) stage, wherein the IC PV stage comprises an absorption region with a band gap, the absorption region configured to absorb photons, an intraband transport region configured to act as a hole barrier, and an interband tunneling region configured to act as an electron barrier. An IC PV architecture for a photovoltaic device, the IC PV architecture comprising an absorption region, an intraband transport region coupled to the absorption region, and an interband tunneling region coupled to the intraband transport region and to the adjacent absorption region, wherein the absorption region, the intraband transport region, and the interband tunneling region are positioned such that electrons will flow from the absorption region to the intraband transport region to the interband tunneling region.

Due to impressive cost reductions in recent years, photovoltaic (PV) generation is now able to produce electricity at highly competitive prices, but PVâs inherent intermittency reduces the potential value of this energy. The integration of battery storage with PV will be transformational by increasing the value of solar. Utility scale systems will benefit by firming intermittency including PV ramp smoothing, grid support and load shifting, allowing PV to compete directly with conventional generation. For distributed grid-tied PV adding storage will reduce peak demand utility charges, as well as providing backup power during power grid failures. The largest long term impact of combined PV and battery systems may be for delivering reliable off-grid power to the billions of individuals globally without access to conventional power grids, or for billions more that suffer from daily power outages. PV module costs no longer dominate installed PV system costs. Balance-of-System (BOS) costs including the PV inverter and installation now contribute the majority of installed system costs. Battery costs are also dropping faster than installation and battery power converter systems. In each of these separate systems power converters have become a bottleneck for efficiency, cost and reliability. These bottlenecks are compounded in hybrid power conversion systems that combine separate PV and battery converters. Hybrid power conversion systems have required multiple power converters hardware units and multiple power conversion steps adding to efficiency losses, product and installation costs, and reliability issues. Ideal Power Converters has developed and patented a completely new theory of operation for electronic power converters using its indirect EnergyPacket Switchingâą topology. It has established successful power converter products for both PV and battery systems, and its 3-Port Hybrid Converter is the first product to exploit the topologyâs capability for the

This was a breakout session at the 2014 SunShot Grand Challenge Summit and Peer Review. The globalPV manufacturing landscape has undergone significant changes in the past decade, from geographic and economic changes in the supply chain to a significant increase in PV module production by fewer manufacturers. The lessons learned over the last decade will guide the future of this growing industry. This session explored the future of PV manufacturing over the next 5 to 10 years, both domestic and abroad. Expert panelists provided their insights and perspectives across three thematic areas: a vision of PV manufacturing, including the level of integration and the factory of the future; value-adding attributes of PV products; and the geographic concentration of PV manufacturing.

Solar photovoltaic (PV) installations have experienced significant growth in recent years. Due to technological innovations and cost reductions, solar energy is a viable option for an increasing number of residences and businesses across the United States. Rooftop solar is considered safe â to date there has been no documented case of death from the electric shock, chemical burn or conventional fire caused by a solar panel; however, as more buildings install rooftop solar systems, the likelihood increases that fires will occur on buildings with solar, making it critical for firefighters to receive comprehensive solar education and training. This SolarOPs fact sheet gives a brief overview of typical solar PV installations, addresses the major hazards and risks to firefighters, discusses fire safety in Germany (the country with the most installed solar PV per capita), and suggests recommendations and resources to ensure that first responders are prepared to fight fires on homes and buildings with rooftop solar PV.

PV News The National Renewable Energy Laboratory Photovoltaic (PV) Research Program highlights latest research and news accomplishments from the laboratory on this page. Subscribe to the RSS feed RSS . Learn about RSS. July 22, 2016 NREL's Kurtz, Tegen Honored for Clean Energy Leadership The U.S. Clean Energy Education & Empowerment (C3E) program has honored Sarah Kurtz and Suzanne Tegen of the Energy Department's National Renewable Energy Laboratory (NREL) for their leadership and

A method for mounting PV modules to a deck includes selecting PV module layout pattern so that adjacent PV module edges are spaced apart. PV mounting and support assemblies are secured to the deck according to the layout pattern using fasteners extending into the deck. The PV modules are placed on the PV mounting and support assemblies. Retaining elements are located over and secured against the upper peripheral edge surfaces of the PV modules so to secure them to the deck with the peripheral edges of the PV modules spaced apart from the deck. In some examples a PV module mounting assembly, for use on a shingled deck, comprises flashing, a base mountable on the flashing, a deck-penetrating fastener engageable with the base and securable to the deck so to secure the flashing and the base to the shingled deck, and PV module mounting hardware securable to the base.

Each PV assembly of an array of PV assemblies comprises a base, a PV module and a support assembly securing the PV module to a position overlying the upper surface of the base. Vents are formed through the base. A pressure equalization path extends from the outer surface of the PV module, past the PV module, to and through at least one of the vents, and to the lower surface of the base to help reduce wind uplift forces on the PV assembly. The PV assemblies may be interengaged, such as by interengaging the bases of adjacent PV assemblies. The base may include a main portion and a cover and the bases of adjacent PV assemblies may be interengaged by securing the covers of adjacent bases together.

Photovoltaic power plants (PVPs) have been growing in size, and the installation time is very short. With the cost of photovoltaic (PV) panels dropping in recent years, it can be predicted that in the next 10 years the contribution of PVPs to the total number of renewable energy power plants will grow significantly. In this project, the National Renewable Energy Laboratory (NREL) developed a dynamic modeling of the modules to be used as building blocks to develop simulation models of single PV arrays, expanded to include Maximum Power Point Tracker (MPPT), expanded to include PV inverter, or expanded to cover an entire PVP. The focus of the investigation and complexity of the simulation determines the components that must be included in the simulation. The development of the PV inverter was covered in detail, including the control diagrams. Both the current-regulated voltage source inverter and the current-regulated current source inverter were developed in PSCAD. Various operations of the PV inverters were simulated under normal and abnormal conditions. Symmetrical and unsymmetrical faults were simulated, presented, and discussed. Both the three-phase analysis and the symmetrical component analysis were included to clarify the understanding of unsymmetrical faults. The dynamic model validation was based on the testing data provided by SCE. Testing was conducted at SCE with the focus on the grid interface behavior of the PV inverter under different faults and disturbances. The dynamic model validation covers both the symmetrical and unsymmetrical faults.

The Connecticut Rooftop Solar PV Permitting Guide is a compilation of best practices and resources for solar PV permitting. The guide includes a summary of current codes and regulations affecting solar PV, best practices for streamlining the municipal permitting process, and tools to assist municipalities in creating a streamlined permit process for residential solar PV. Resources include a solar PV permit application, a structural review worksheet, an inspection checklist, and a model solar zoning ordinance.

As the photovoltaics (PV) industry has grown, the need for accurately monitoring the solar resource of PV power plants has increased. Historically, the PV industry has relied on thermopile pyranometers for irradiance measurements, and a large body of historical irradiance data taken with pyranometers exists. However, interest in PV reference devices is increasing. In this paper, we discuss why PV reference devices are better suited for PV applications, and estimate the typical uncertainties in irradiance measurements made with both pyranometers and PV reference devices. We assert that the quantity of interest in monitoring a PV power plant is the equivalent irradiance under the IEC 60904-3 reference solar spectrum that would produce the same electrical response in the PV array as the incident solar radiation. For PV-plant monitoring applications, we find the uncertainties in irradiance measurements of this type to be on the order of +/-5% for thermopile pyranometers and +/-2.4% for PV reference devices.

This webinar provides an overview of Connecticut's Structural Review Worksheet for Residential Rooftop Solar PV Systems. The webinar explains how the worksheet should be used and common concerns with wind and dead loads for rooftop solar PV.

The Open PV Project The Open PV Project The Open PV Project is a collaborative effort between government, industry, and the public that is compiling a comprehensive database of photovoltaic (PV) installation data for the United States. Data for the project is voluntarily contributed from a variety of sources including utilities, installers, and the general public. The data collected is actively maintained by the contributors and are always changing to provide an evolving, up-to-date snapshot of

| Department of Energy GE Plant to Produce Thin Film PV Solar Panels Based on NREL Technology New GE Plant to Produce Thin Film PV Solar Panels Based on NREL Technology April 22, 2011 - 10:17am Addthis Photo courtesy of General Electric Photo courtesy of General Electric Minh Le Minh Le Deputy Director, Solar Energy Technologies Office Earlier this month, General Electric announced plans to enter the global marketplace for solar photovoltaic (PV) panels in a big way - and to do it, they will

Project Objective: To procure a photovoltaic array (PV) system which will generate approximately 256kW of power to be used for the operations of the Aquatic Complex and the adjacent Senior Facility at the Heritage Park. This project complies with the EEREâs work and objectives by promoting the development and deployment of an energy system that will provide current and future generations with clean, efficient, affordable, and reliable energy.

PV Validation and Bankability Workshop What if?? * This is a reality: A subsidy-free solar electricity infrastructure with an LCOE of 5-6 c/kWh without subsidies * Jobs and Competitiveness: Innovation that ensures the U.S. leads the way on clean energy, supporting new jobs and opportunities for Americans * National Energy Security: Independence from fossil fuel and increased national security * Healthy Environment: Huge carbon reduction and cleaner air ... Imagine a World... * Introducing

This report describes an algorithm, implemented in Matlab/Simulink, designed to reduce the variability of photovoltaic (PV) power output by using a battery. The purpose of the battery is to add power to the PV output (or subtract) to smooth out the high frequency components of the PV power that that occur during periods with transient cloud shadows on the PV array. The control system is challenged with the task of reducing short-term PV output variability while avoiding overworking the battery both in terms of capacity and ramp capability. The algorithm proposed by Sandia is purposely very simple to facilitate implementation in a real-time controller. The control structure has two additional inputs to which the battery can respond. For example, the battery could respond to PV variability, load variability or area control error (ACE) or a combination of the three.

Photovoltaic (PV) customers need to have confidence in the PV modules they purchase. Currently, no test can quantify a module's lifetime with confidence, but stress tests are routinely used to differentiate PV product designs. We suggest that the industry would be strengthened by using the wisdom of the community to develop a single set of tests that will help customers quantify confidence in PV products. This paper evaluates the need for quality assurance (QA) standards and suggests a path for creating these. Two types of standards are needed: 1) QA of the module design and 2) QA of the manufacturing process.

PV Validation and Bankability Workshop August 31, 2011 Survey Results As of August 29, 2011 List of Questions * What is your market sector? * From product development through product launch, data must be collected at each step. If the Department of Energy can identify funds to provide some type of 3rd party validation/verification effort/study, what would be your priority for that effort? * What scale of module/system data is of interest and of use in making decisions in your market sector? *

Webinar on navigating the legal, tax, and finance issues associated with the installation of Municipal PV Systems. The following agenda was developed based on Pat Boylston's experience assisting municipalities with their PV projects and the requests for information that the Solar America City technical team leads have received from many of the 25 Solar America Cities since the April 2008 meeting in Tucson.

This webinar provides training on two permitting resources for municipal inspectors; a prescriptive process for building inspectors and a guidance document for permitting for PV for electrical inspectors. The webinar also runs through a number of key code articles in Massachusetts 2014 electrical code and examines a variety of safety hazards commonly found during or after solar PV installations.

The evolution of PV into one of the world's largest industries is not going to happen without major unforeseen problems. However, this study attempts to address the obvious ones, so that we can put aside the mythology of PV (for example, that it is only ''boutique power'' or that one must pave the world with it to be useful) and get on with changing the world's energy infrastructure. With the years of rapid market growth now under way in PV, the author is sure this will not be the last effort to understand the real potential and pitfalls of meeting the Challenge.

NREL has used its dSolar (distributed solar) model to generate low-medium-high estimates of distributed PV adoption in Maine through 2021. This presentation gives a high-level overview of the model and modeling results.

This National Center for Photovoltaics sheet describes the capabilities of its PV module reliability research. The scope and core competencies and capabilities are discussed and recent publications are listed.

This presentation describes a comparison of the "predicted" energy (based on historical weather data) with the "expected" energy (based on the measured weather data) to determine whether a PV system is performing as modeled in order to verify the accuracy of a model. A key factor in defining this energy test is determining the test boundary so that weather variations are not inadvertently included in what is considered to be PV system performance.

Lessons Learned with Early PV Plant Integration" Elsa Gonzalez, Rachel Sall, Frankie Greco and David Narang with Arizona Public Service Company June 12, 2014 2 Speakers Frankie Greco Distribution Interconnection Team Arizona Public Service Company Elsa Gonzales Distribution Operations Engineer Arizona Public Service Company David Narang Senior Engineer Arizona Public Service Company Rachel Sall Arizona Public Service Company Lessons Learned with Early PV Plant Integration Elsa Gonzalez

Solar photovoltaics (PV) is the dominant type of distributed generation (DG) technology interconnected to electric distribution systems in the United States, and deployment of PV systems continues to increase rapidly. Considering the rapid growth and widespread deployment of PV systems in United States electric distribution grids, it is important that interconnection procedures be as streamlined as possible to avoid unnecessary interconnection studies, costs, and delays. Because many PV interconnection applications involve high penetration scenarios, the process needs to allow for a sufficiently rigorous technical evaluation to identify and address possible system impacts. Existing interconnection procedures are designed to balance the need for efficiency and technical rigor for all DG. However, there is an implicit expectation that those procedures will be updated over time in order to remain relevant with respect to evolving standards, technology, and practical experience. Modifications to interconnection screens and procedures must focus on maintaining or improving safety and reliability, as well as accurately allocating costs and improving expediency of the interconnection process. This paper evaluates the origins and usefulness of the capacity penetration screen, offers potential short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen.

The purpose of this work consists in thermodynamic modeling of hybrid photovoltaic-thermal (PV/T) solar systems, pursuing a modular strategy approach provided by Simulink/Matlab. PV/T solar systems are a recently emerging solar technology that allows for the simultaneous conversion of solar energy into both electricity and heat. This type of technology present some interesting advantages over the conventional ''side-by-side'' thermal and PV solar systems, such as higher combined electrical/thermal energy outputs per unit area, and a more uniform and aesthetical pleasant roof area. Despite the fact that early research on PV/T systems can be traced back to the seventies, only recently it has gained a renewed impetus. In this work, parametric studies and annual transient simulations of PV/T systems are undertaken in Simulink/Matlab. The obtained results show an average annual solar fraction of 67%, and a global overall efficiency of 24% (i.e. 15% thermal and 9% electrical), for a typical four-person single-family residence in Lisbon, with p-Si cells, and a collector area of 6 m{sup 2}. A sensitivity analysis performed on the PV/T collector suggests that the most important variable that should be addressed to improve thermal performance is the photovoltaic (PV) module emittance. Based on those results, some additional improvements are proposed, such as the use of vacuum, or a noble gas at low-pressure, to allow for the removal of PV cells encapsulation without air oxidation and degradation, and thus reducing the PV module emittance. Preliminary results show that this option allows for an 8% increase on optical thermal efficiency, and a substantial reduction of thermal losses, suggesting the possibility of working at higher fluid temperatures. The higher working temperatures negative effect in electrical efficiency was negligible, due to compensation by improved optical properties. The simulation results are compared with experimental data obtained from other authors

International standards play an important role in the Photovoltaic industry. Since PV is such a global industry it is critical that PV products be measured and qualified the same way everywhere in the world. IEC TC82 has developed and published a number of module and component measurement and qualification standards. These are continually being updated to take advantage of new techniques and equipment as well as better understanding of test requirements. Standards presently being updated include the third edition of IEC 61215, Crystalline Silicon Qualification and the second edition of IEC 61730, PV Module Safety Requirements. New standards under development include qualification of junction boxes, connectors, PV cables, and module integrated electronics as well as for testing the packaging used during transport of modules. After many years of effort, a draft standard on Module Energy Rating should be circulated for review soon. New activities have been undertaken to develop standards for the materials within a module and to develop tests that evaluate modules for wear-out in the field (International PV Module QA Task Force). This paper will discuss these efforts and indicate how the audience can participate in development of international standards.

Much in demand are next-generation photovoltaic (PV) technologies that can be used economically to make a large-scale impact on world electricity production. The U.S. Department of Energy (DOE) initiated the High-Performance Photovoltaic (HiPerf PV) Project to substantially increase the viability of PV for cost-competitive applications so that PV can contribute significantly to both our energy supply and environment. To accomplish such results, the National Center for Photovoltaics (NCPV) directs in-house and subcontracted research in high-performance polycrystalline thin-film and multijunction concentrator devices with the goal of enabling progress of high-efficiency technologies toward commercial-prototype products. We will describe the details of the subcontractor and in-house progress in exploring and accelerating pathways of III-V multijunction concentrator solar cells and systems toward their long-term goals. By 2020, we anticipate that this project will have demonstrated 33% system efficiency and a system price of $1.00/Wp for concentrator PV systems using III-V multijunction solar cells with efficiencies over 41%.

During the development of a solar photovoltaic (PV) energy project, predicting expected energy production from a system is a key part of understanding system value. System energy production is a function of the system design and location, the mounting configuration, the power conversion system, and the module technology, as well as the solar resource. Even if all other variables are held constant, annual energy yield (kWh/kWp) will vary among module technologies because of differences in response to low-light levels and temperature. A number of PV system performance models have been developed and are in use, but little has been published on validation of these models or the accuracy and uncertainty of their output. With support from the U.S. Department of Energy's Solar Energy Technologies Program, Sandia National Laboratories organized a PV Performance Modeling Workshop in Albuquerque, New Mexico, September 22-23, 2010. The workshop was intended to address the current state of PV system models, develop a path forward for establishing best practices on PV system performance modeling, and set the stage for standardization of testing and validation procedures for models and input parameters. This report summarizes discussions and presentations from the workshop, as well as examines opportunities for collaborative efforts to develop objective comparisons between models and across sites and applications.

The main obstacle Photovoltaic (PV) industry is facing at present is the higher cost of PV energy compared to that of fossil energy. While solar cell efficiencies continue to make incremental gains these improvements are so far insufficient to drive PV costs down to match that of fossil energy. Improved in-line diagnostics however, has the potential to significantly increase the productivity and reduce cost by improving the yield of the process. On this Phase I/Phase II SBIR project MicroXact developed and demonstrated at CIGS pilot manufacturing line a high-throughput in-line PV manufacturing diagnostic system, which was verified to provide fast and accurate data on the spatial uniformity of thickness, an composition of the thin films comprising the solar cell as the solar cell is processed reel-to-reel. In Phase II project MicroXact developed a stand-alone system prototype and demonstrated the following technical characteristics: 1) ability of real time defect/composition inconsistency detection over 60cm wide web at web speeds up to 3m/minute; 2) Better than 1mm spatial resolution on 60cm wide web; 3) an average better than 20nm spectral resolution resulting in more than sufficient sensitivity to composition imperfections (copper-rich and copper-poor regions were detected). The system was verified to be high vacuum compatible. Phase II results completely validated both technical and economic feasibility of the proposed concept. MicroXactâs solution is an enabling technique for in-line PV manufacturing diagnostics to increase the productivity of PV manufacturing lines and reduce the cost of solar energy, thus reducing the US dependency on foreign oil while simultaneously reducing emission of greenhouse gasses.

Schmidt Unit Title: Circuits and Electricity Subject: Physics Lesson Title: Investigating Temperature Effects on PV Arrays Grade Level(s): 11/12 Date(s): July 18, 2014 Lesson Length: 1 Class Period (65 minutes) * Learning Goal(s) [What should students know, understand, or be able to do as a result of this lab or activity.] Students will be able to measure current and voltage using a Multimeter. Students will be able to calculate the power of a PV array using voltage and current. Students will

This research effort evaluates the impact of large-scale photovoltaic (PV) and distributed generation (DG) output on NV Energyâs electric grid system in southern Nevada. It analyzes the ability of NV Energyâs generation to accommodate increasing amounts of utility-scale PV and DG, and the resulting cost of integrating variable renewable resources. The study was jointly funded by the United States Department of Energy and NV Energy, and conducted by a project team comprised of industry experts and research scientists from Navigant Consulting Inc., Sandia National Laboratories, Pacific Northwest National Laboratory and NV Energy.

This white paper evaluates the origins and usefulness of the capacity penetration screen, offer short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen. Short-term and longer-term alternatives approaches are offered as examples; however, specific modifications to screening procedures should be discussed with stakeholders and must ultimately be adopted by state and federal regulatory bodies.

The International PV Quality Assurance Task Force is developing a rating system that provides comparative information about the relative durability of PV modules. Development of accelerated stress tests that can provide such comparative information is seen as a major step toward being able to predict PV module service life. This paper will provide details of the ongoing effort to determine the format of such an overall module rating system. The latest proposal is based on using three distinct climate zones as defined in IEC 60721-2-1 for two different mounting systems. Specific stresses beyond those used in the qualification tests are being developed for each of the selected climate zones.

The price of photovoltaic (PV) systems in the United States (i.e., the cost to the system owner) has dropped precipitously in recent years, led by substantial reductions in globalPV module prices. However, system cost reductions are not necessarily realized or realized in a timely manner by many customers. Many reasons exist for the apparent disconnects between installation costs, component prices, and system prices; most notable is the impact of fair market value considerations on system prices. To guide policy and research and development strategy decisions, it is necessary to develop a granular perspective on the factors that underlie PV system prices and to eliminate subjective pricing parameters. This report's analysis of the overnight capital costs (cash purchase) paid for PV systems attempts to establish an objective methodology that most closely approximates the book value of PV system assets.

Silicon photovoltaic (PV) technologies are addressed in two different technology roadmaps: Film-Silicon PV and Wafer-Silicon PV. This Film-Silicon PV roadmap applies to all silicon-film technologies that rely on a supporting substrate such as glass, polymer, aluminum, stainless steel, or metallurgical-grade silicon. Such devices typically use amorphous, nanocrystalline, fine-grained polycrystalline, or epitaxial silicon layers that are 1â20 ÎŒm thick.

The Permit Application Checklist is intended to be used as a best management practice when establishing local government requirements for residential and commercial solar photovoltaic (PV) system permits. Local governments may modify this checklist to accommodate their local ordinances, code requirements, and permit procedures.

The purpose of this assessment is to provide site-specific information on how a solar electric (also referred to as a photovoltaic, or PV) system would perform at your location, including information on estimated physical size, rated output, energy production, costs, financial incentives and mounting options. Site assessors are required to present unbiased information and may not recommend contractors or products.

The PV Fault Detection Tool project plans to demonstrate that the FDT can (a) detect catastrophic and degradation faults and (b) identify the type of fault. This will be accomplished by collecting fault signatures using different instruments and integrating this information to establish a logical controller for detecting, diagnosing and classifying each fault.

This paper discusses the developments in thin-film PV technologies and provides an outlook on future commercial module efficiencies achievable based on today's knowledge about champion cell performance.

The project described in this report was a commercialization effort focused on cost-effective remote water pumping systems for use in utility-based photovoltaic (PV) service programs. The project combined a commercialization strategy tailored specifically for electric utilities with the development of a PV-powered pumping system that operates conventional ac pumps rather than relying on the more expensive and less reliable PV pumps on the market. By combining these two attributes, a project goal was established of creating sustained utility purchases of 250 PV-powered water pumping systems per year. The results of each of these tasks are presented in two parts contained in this Final Summary Report. The first part summarizes the results of the Photovoltaic Services Network (PSN) as a new business venture, while the second part summarizes the results of the Golden Photon system installations. Specifically, results and photographs from each of the system installations are presented in this latter part.

NREL has contracted with Clean Power Research to provide 1-minute simulation datasets of PV systems located at three high penetration distribution feeders in the service territory of Southern California Edison (SCE): Porterville, Palmdale, and Fontana, California. The resulting PV simulations will be used to separately model the electrical circuits to determine the impacts of PV on circuit operations.

PV_LIB comprises a library of Matlab? code for modeling photovoltaic (PV) systems. Included are functions to compute solar position and to estimate irradiance in the PV systemÂs plane of array, cell temperature, PV module electrical output, and conversion from DC to AC power. Also included are functions that aid in determining parameters for module performance models from module characterization testing. PV_LIB is open source code primarily intended for research and academic purposes. All algorithms are documented in openly available literature with the appropriate references included in comments within the code.

PV_LIB comprises a library of Matlab? code for modeling photovoltaic (PV) systems. Included are functions to compute solar position and to estimate irradiance in the PV systemÂs plane of array, cell temperature, PV module electrical output, and conversion from DC to AC power. Also included are functions that aid in determining parameters for module performance models from module characterization testing. PV_LIB is open source code primarily intended for research and academic purposes. All algorithms aremoreÂ Â» documented in openly available literature with the appropriate references included in comments within the code.Â«Â less

In this project, a team led by Delphi will develop and demonstrate a novel cascaded photovoltaic (PV) inverter architecture using advanced components. This approach will reduce the cost and improve the performance of medium and large-sized PV systems. The overall project objective is to develop, build, and test a modular 11-level cascaded three-phase inverter building block for photovoltaic applications and to develop and analyze the associated commercialization plan. The system will be designed to utilize photovoltaic panels and will supply power to the electric grid at 208 VAC, 60 Hz 3-phase. With the proposed topology, three inverters, each with an embedded controller, will monitor and control each of the cascade sections, reducing costs associated with extra control boards. This report details the final disposition on this project.

Lessons Learned with Early PV Plant Integration Page 1 of 23 Kristen Ardani (NREL), Elsa Gonzales (Arizona Public Service Company), Rachel Sall (Arizona Public Service Company), Frankie Greco (Arizona Public Service Company), David Narang (Arizona Public Service Company) Page 1 of 23 [Speaker: Kristen Ardani] Cover Slide: Thank you everyone for joining us today for the DG Interconnection Collaborative informational webinar. Today we have speakers from Arizona Public Service Company, who will

Program Description SAGE, the Summer of Applied Geophysical Experience, is a unique educational program designed to introduce students in geophysics and related fields to "hands on" geophysical exploration and research. The program emphasizes both teaching of field methods and research related to basic science and a variety of applied problems. SAGE is hosted by the National Security Education Center and the Earth and Environmental Sciences Division of the Los Alamos National

This study develops a systematic framework for estimating the increase in operating costs due to uncertainty and variability in renewable resources, uses the framework to quantify the integration costs associated with sub-hourly solar power variability and uncertainty, and shows how changes in system operations may affect these costs. Toward this end, we present a statistical method for estimating the required balancing reserves to maintain system reliability along with a model for commitment and dispatch of the portfolio of thermal and renewable resources at different stages of system operations. We estimate the costs of sub-hourly solar variability, short-term forecast errors, and day-ahead (DA) forecast errors as the difference in production costs between a case with ârealisticâ PV (i.e., subhourly solar variability and uncertainty are fully included in the modeling) and a case with âwell behavedâ PV (i.e., PV is assumed to have no sub-hourly variability and can be perfectly forecasted). In addition, we highlight current practices that allow utilities to compensate for the issues encountered at the sub-hourly time frame with increased levels of PV penetration. In this analysis we use the analytical framework to simulate utility operations with increasing deployment of PV in a case study of Arizona Public Service Company (APS), a utility in the southwestern United States. In our analysis, we focus on three processes that are important in understanding the management of PV variability and uncertainty in power system operations. First, we represent the decisions made the day before the operating day through a DA commitment model that relies on imperfect DA forecasts of load and wind as well as PV generation. Second, we represent the decisions made by schedulers in the operating day through hour-ahead (HA) scheduling. Peaking units can be committed or decommitted in the HA schedules and online units can be redispatched using forecasts that are improved

Grid-connected photovoltaic (PV) systems with power electronic interfaces can provide both real and reactive power to meet power system needs with appropriate control algorithms. This paper presents the control algorithm design for a three-phase single-stage grid-connected PV inverter to achieve either maximum power point tracking (MPPT) or a certain amount of real power injection, as well as the voltage/var control. The switching between MPPT control mode and a certain amount of real power control mode is automatic and seamless. Without the DC-to-DC booster stage, PV DC voltage stability is an important issue in the control design especially when the PV inverter is operating at maximum power point (MPP) with voltage/var control. The PV DC voltage collapse phenomenon and its reason are discussed. The method based on dynamic correction of the PV inverter output is proposed to ensure PV DC voltage stability. Simulation results of the single-stage PV system during system disturbances and fast solar irradiation changes confirm that the proposed control algorithm for single-stage PV inverters can provide appropriate real and reactive power services and ensure PV DC voltage stability during dynamic system operation and atmospheric conditions.

The price of photovoltaic (PV) systems in the United States (i.e., the cost to the system owner) has dropped precipitously in recent years, led by substantial reductions in globalPV module prices. This report provides a Q4 2013 update for residential PV systems, based on an objective methodology that closely approximates the book value of a PV system. Several cases are benchmarked to represent common variation in business models, labor rates, and module choice. We estimate a weighted-average cash purchase price of $3.29/W for modeled standard-efficiency, polycrystalline-silicon residential PV systems installed in the United States. This is a 46% decline from the 2013-dollar-adjusted price reported in the Q4 2010 benchmark report. In addition, this report frames the cash purchase price in the context of key price metrics relevant to the continually evolving landscape of third-party-owned PV systems by benchmarking the minimum sustainable lease price and the fair market value of residential PV systems.

Energy Systems Integration | NREL Releases High-Penetration PV Handbook for Distribution Engineers A new resource sponsored by the Energy Department's SunShot Initiative helps distribution engineers understand the challenges of high-penetration PV integration. January 27, 2016 As solar photovoltaic (PV) systems are increasingly installed throughout the country at distribution-level utility scale, a new challenge is emerging: how to safely and effectively integrate greater amounts of variable

Grid Modernization | NREL Releases High-Penetration PV Handbook for Distribution Engineers A new resource sponsored by the Energy Department's SunShot Initiative helps distribution engineers understand the challenges of high-penetration PV integration. January 27, 2016 As solar photovoltaic (PV) systems are increasingly installed throughout the country at distribution-level utility scale, a new challenge is emerging: how to safely and effectively integrate greater amounts of variable solar

Releases | NREL Helps Establish New PV Quality Standards for Manufacturers February 8, 2016 Working with partners around the world, researchers at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have completed five years of work toward helping establish an international quality standard for manufacturing photovoltaic (PV) modules. PV manufacturers will use the new standard to increase the level of confidence investors, utilities, and consumers have in solar panel

for Distribution Engineers Releases High-Penetration PV Handbook for Distribution Engineers A new resource sponsored by the Energy Department's SunShot Initiative helps distribution engineers understand the challenges of high-penetration PV integration. January 27, 2016 As solar photovoltaic (PV) systems are increasingly installed throughout the country at distribution-level utility scale, a new challenge is emerging: how to safely and effectively integrate greater amounts of variable solar

This report summarizes the work performed by Delmarva Power and Light and its subcontractors in Phase 1 of the US Department of Energy's PV:BONUS Program. The purpose of the program is to develop products and systems for buildings which utilize photovoltaic (N) technology. Beginning with a cooperative research effort with the University of Delaware's Center for Energy and Environmental Policy Research Delmarva Power developed and demonstrated the concept of Dispatchable PV Peak Shaving. This concept and the system which resulted horn the development work are unique from other grid-connected PV systems because it combines a PV, battery energy storage, power conversion and control technologies into an integrated package. Phase 1 began in July 1993 with the installation of a test and demonstration system at Delmarva's Northern Division General Office building near Newark, Delaware. Following initial testing throughout the summer and fall of 1993, significant modifications were made under an amendment to the DOE contract. Work on Phase 1 concluded in the early spring of 1995. Significant progress towards the goal of commercializing the system was made during Phase 1, and is summarized. Based on progress in Phase 1, a proposal to continue the work in Phase 2 was submitted to the US DOE in May 1995. A contract amendment and providing funds for the Phase 2 work is expected in July 1995.

This analysis provides a detailed national and regional description of the water-related impacts and constraints of high solar electricity penetration scenarios in the U.S. in 2030 and 2050. A modified version of the Regional Energy Deployment System (ReEDS) model that incorporates water resource availability and costs as a constraint in each of its 134 Balancing Area (BA) regions was utilized to explore national and regional differences in water use impacts and solar deployment locations under different solar energy cost and water availability scenarios (Macknick et al. 2015). Water resource availability and cost data are from recently completed research at Sandia National Laboratories (Tidwell et al. 2013a). Scenarios analyzed include two business-as-usual solar energy cost cases, one with and one without considering available water resources, and four solar energy cost cases that meet the SunShot cost goals (i.e., $1/watt for utility-scale PV systems), with varying levels of water availability restrictions. This analysis provides insight into the role solar energy technologies have in the broader electricity sector under scenarios of water constraints.

a Recurrent Neural Network PV System Model with a Traditional Component-Based PV System Model Daniel Riley, Sandia National Laboratories, Albuquerque, New Mexico, USA | Ganesh K. Venayagamoorthy, Missouri University of Science and Technology, Rolla, Missouri, USA Abstract Traditional PV system modeling approaches require system components to be tested in order to determine performance parameters. In some cases, system owners may wish to predict system performance, but lack the parameters

This paper describes the implementation of a program intended to introduce PV based hybrid power systems to supply electrical power to small size TV rebroadcast stations in Portugal. Reliability is a major concern to this type of application, as well as economical and social constraints, so wind or diesel/LPG genset backup are used. This paper includes a description of the systems behavior, comparison among these topologies and economical viability data from a users viewpoint.

Grid tied PV energy smoothing was implemented by using a valve regulated lead-acid (VRLA) battery as a temporary energy storage device to both charge and discharge as required to smooth the inverter energy output from the PV array. Inverter output was controlled by the average solar irradiance over the previous 1h time interval. On a clear day the solar irradiance power curve is offset by about 1h, while on a variable cloudy day the inverter output power curve will be smoothed based on the average solar irradiance. Test results demonstrate that this smoothing algorithm works very well. Battery state of charge was more difficult to manage because of the variable system inefficiencies. Testing continued for 30-days and established consistent operational performance for extended periods of time under a wide variety of resource conditions. Both battery technologies from Exide (Absolyte) and East Penn (ALABC Advanced) proved to cycle well at a Partial state of charge over the time interval tested.

The price of electricity supplied from home rooftop photo voltaic (PV) solar cells has fallen below the retail price of grid electricity in some areas. A number of residential households have an economic incentive to install rooftop PV systems and reduce their purchases of electricity from the grid. A significant portion of the costs incurred by utility companies are fixed costs which must be recovered even as consumption falls. Electricity rates must increase in order for utility companies to recover fixed costs from shrinking sales bases. Increasing rates will, in turn, result in even more economic incentives for customers to adopt rooftop PV. In this paper, we model this feedback between PV adoption and electricity rates and study its impact on future PV penetration and net-metering costs. We find that the most important parameter that determines whether this feedback has an effect is the fraction of customers who adopt PV in any year based solely on the money saved by doing so in that year, independent of the uncertainties of future years. These uncertainties include possible changes in rate structures such as the introduction of connection charges, the possibility of PV prices dropping significantly in the future, possible changes in tax incentives, and confidence in the reliability and maintainability of PV. (C) 2013 Elsevier Ltd. All rights reserved.

The High-Performance Photovoltaic (HiPerf PV) Project was initiated by the U.S. Department of Energy to substantially increase the viability of photovoltaics (PV) for cost-competitive applications so that PV can contribute significantly to our energy supply and our environment. The HiPerf PV Project aims at exploring the ultimate performance limits of existing PV technologies, approximately doubling their sunlight-to-electricity conversion efficiencies during its course. This work includes bringing thin-film cells and modules toward 25% and 20% efficiencies, respectively, and developing multijunction concentrator cells and modules able to convert more than one-third of the sun's energy to electricity (i.e., 33% efficiency). This paper will address recent accomplishments of the NREL in-house research effort involving polycrystalline thin-film tandems, as well as the research efforts under way in the subcontracted area.

There is growing national interest in renewable energy development based on the economic, environmental, and security benefits that these resources provide. Historically, greater development of our domestic renewable energy resources has faced a number of hurdles, primarily related to cost, regulation, and financing. With the recent sustained increase in the costs and associated volatility of fossil fuels, the economics of renewable energy technologies have become increasingly attractive to investors, both large and small. As a result, new entrants are investing in renewable energy and new business models are emerging. This study surveys some of the current issues related to wind and solar photovoltaic (PV) energy project financing in the electric power industry, and identifies both barriers to and opportunities for increased investment.

As photovoltaic (PV) penetration of the power grid increases, it becomes vital to know how decreased power output may affect cost over time. In order to predict power delivery, the decline or degradation rates must be determined accurately. For non-spectrally corrected data several complete seasonal cycles (typically 3-5 years) are required to obtain reasonably accurate degradation rates. In a rapidly evolving industry such a time span is often unacceptable and the need exists to determine degradation rates accurately in a shorter period of time. Occurrence of outliers and data shifts are two examples of analytical problems leading to greater uncertainty and therefore to longer observation times. In this paper we compare three methodologies of data analysis for robustness in the presence of outliers, data shifts and shorter measurement time periods.

This report investigates the effects that increased distributed photovoltaic (PV) generation would have on the Kauai Island Utility Co-op (KIUC) system operating requirements. The study focused on determining reserve requirements needed to mitigate the impact of PV variability on system frequency, and the impact on operating costs. Scenarios of 5-MW, 10-MW, and 15-MW nameplate capacity of PV generation plants distributed across the Kauai Island were considered in this study. The analysis required synthesis of the PV solar resource data and modeling of the KIUC system inertia. Based on the results, some findings and conclusions could be drawn, including that the selection of units identified as marginal resources that are used for load following will change; PV penetration will displace energy generated by existing conventional units, thus reducing overall fuel consumption; PV penetration at any deployment level is not likely to reduce system peak load; and increasing PV penetration has little effect on load-following reserves. The study was performed by EnerNex under contract from Sandia National Laboratories with cooperation from KIUC.

Solar photovoltaic (PV) systems hold great potential for distributed energy generation by installing PV panels on rooftops of residential and commercial buildings. Yet challenges arise along with the variability and non-dispatchability of the PV systems that affect the stability of the grid and the economics of the PV system. This paper investigates the integration of PV arrays for distributed generation applications by identifying a combination of buildings that will maximize solar energy output and minimize system variability. Particularly, we propose mean-variance optimization models to choose suitable rooftops for PV integration based on Markowitz mean-variance portfolio selection model. We further introduce quantity and cardinality constraints to result in a mixed integer quadratic programming problem. Case studies based on real data are presented. An efficient frontier is obtained for sample data that allows decision makers to choose a desired solar energy generation level with a comfortable variability tolerance level. Sensitivity analysis is conducted to show the tradeoffs between solar PV energy generation potential and variability.

This is one of two companion papers that describe the ENERGY-10 PV design-tool computer simulation program. The other paper is titled ''Hourly Simulation of Grid-Connected PV Systems Using Realistic Building Loads.'' While this paper focuses on the implementation method, the companion paper focuses on the PV aspects of the program. The case study in this paper is a residential building application, whereas the case study in the companion paper is a commercial application with an entirely different building load characteristic. Together, they provide a balanced view.

This report is a collaboration between Sandia National Laboratories, the National Renewable Energy Laboratory, and the Florida Solar Energy Center (FSEC). The report provides feedback from the U.S. Department of Energy's (DOE) Solar Program PV Validation and Bankability Workshop in San Jose, California on August 31, 2011. It focuses on the current state of PV in the United States, private funding to fund U.S. PV industry growth, roles and functions of the regional test center program, and ways to improve the current validation and bankability practices.

This conference paper describes the High-Performance Photovoltaic (HiPerf PV)Project was initiated by the U.S. Department of Energy to substantially increase the viability of photovoltaics (PV) for cost-competitive applications so that PV can contribute significantly to our energy supply and our environment in the 21st century. To accomplish this, the NCPV directs in-house and subcontracted research in high-performance polycrystalline thin-film and multijunction concentrator devices. Details of the subcontractor and in-house progress will be described toward identifying critical pathways of 25% polycrystalline thin-film tandem cells and developing multijunction concentrator modules to 33%.

When designing a photovoltaic (PV) system for northern climates, the prospective installation should be evaluated with respect to the potentially detrimental effects of snow preventing solar radiation from reaching the PV cells. The extent to which snow impacts performance is difficult to determine because snow events also increase the uncertainty of the solar radiation measurement, and the presence of snow needs to be distinguished from other events that can affect performance. This paper describes two instruments useful for evaluating PV system performance losses from the presence of snow: (1) a pyranometer with a heater to prevent buildup of ice and snow, and (2) a digital camera for remote retrieval of images to determine the presence of snow on the PV array.

This 5-page technical letter addresses air pollution effects on PV performance by quantifying, based on a literature search, the average annual loss due to soiling, the impact of cleaning, and a recommended cleaning schedule.

In October 2008, the United States Congress extended both the residential and commercial solar investment tax credits (ITCs) for an unprecedented eight years, lifted the $2,000 cap on the residential credit, removed the prohibition on utility use of the commercial credit, and eliminated restrictions on the use of both credits in conjunction with the Alternative Minimum Tax. These significant changes, which apply to systems placed in service on or after January 1, 2009, will increase the value of the solar credits for residential system owners in particular, and are likely--in conjunction with state, local, and utility rebate programs targeting solar--to spur significant growth in residential, commercial, and utility-scale photovoltaic (PV) installations in the years ahead. This article focuses specifically on the residential credit, describing three areas in which removal of the $2,000 cap on the residential ITC will have significant implications for PV rebate program administrators, PV system owners, and the PV industry.

The U.S. Department of Energy (DOE) has teamed with cities across the country through the Solar America Cities (SAC) partnership program to help reduce barriers and accelerate implementation of solar energy. The New York City SAC team is a partnership between the City University of New York (CUNY), the New York City Mayor s Office of Long-term Planning and Sustainability, and the New York City Economic Development Corporation (NYCEDC).The New York City SAC team is working with DOE s National Renewable Energy Laboratory (NREL) and Con Edison, the local utility, to develop a roadmap for photovoltaic (PV) installations in the five boroughs. The city set a goal to increase its installed PV capacity from1.1 MW in 2005 to 8.1 MW by 2015 (the maximum allowed in 2005). A key barrier to reaching this goal, however, is the complexity of the interconnection process with the local utility. Unique challenges are associated with connecting distributed PV systems to secondary network distribution systems (simplified to Ă?Â?Ă?ÂąĂ?Â?Ă?Â?Ă?Â?Ă?Â?networksĂ?Â?Ă?ÂąĂ?Â?Ă?Â?Ă?Â?Ă?Â in this report). Although most areas of the country use simpler radial distribution systems to distribute electricity, larger metropolitan areas like New York City typically use networks to increase reliability in large load centers. Unlike the radial distribution system, where each customer receives power through a single line, a network uses a grid of interconnected lines to deliver power to each customer through several parallel circuits and sources. This redundancy improves reliability, but it also requires more complicated coordination and protection schemes that can be disrupted by energy exported from distributed PV systems. Currently, Con Edison studies each potential PV system in New York City to evaluate the system s impact on the network, but this is time consuming for utility engineers and may delay the customer s project or add cost for larger installations. City leaders would like to streamline

Business Opportunity Solar PV Recycling Identified as Untapped Business Opportunity June 27, 2016 A new report, End-of-Life Management: Solar Photovoltaic Panels, highlights that recycling or repurposing solar PV panels at the end of their roughly 30-year lifetime can unlock a large stock of raw materials and other valuable components. The report, co-authored by NREL, the International Renewable Energy Agency (IRENA) and the International Energy Agency's Photovoltaic Power Systems Programme

Device Tosses Out Unusable PV Wafers January 11, 2013 Photo of a scientist in safety glasses using tweezers to hold a rectangular gray silicon wafer. He is about to load it into a large silver-metallic instrument. Enlarge image NREL postdoctoral scientist Rene Rivero readies a wafer for the Silicon Photovoltaic Wafer Screening System. Credit: Dennis Schroeder Silicon wafers destined to become photovoltaic (PV) cells can take a bruising through assembly lines, as they are oxidized, annealed,

Computational scheme for designing photovoltaic (PV) materials is presented. First-principles electron dynamics of photo-excitation and subsequent electron-hole splitting is performed based on the time-dependent density functional theory. Photo-induced enhancement of dipole moment was observed in a polar crystal and a donor-acceptor molecular pair. These experiences will pave a way to design PV material from first-principles simulations.

Department of Energy's Loan Programs O ce (LPO) was instrumental in launching the utility-scale photovoltaic (PV) solar industry in the United States. In 2009, there was not a single PV solar facility larger than 100 megawatts (MW) operating in the United States. Despite growing demand for this clean, renewable energy source, developers faced challenges securing the financing necessary to build these large projects. LPO stepped in to address this market barrier by providing more than $4.6

Energy Systems Integration | NREL Integrating PV in Distributed Grids: Solutions and Technologies Workshop In October 2015, NREL's Energy Systems Integration team hosted a workshop on ways to safely integrate more photovoltaics (PV) onto the grid. The workshop was held at the Energy Systems Integration Facility. Presenters from industry, vendors, academia, NREL, and the U.S. Department of Energy participated in the workshops, bringing a broad perspective to the discussions. Below are

Designing new solar projects to be 'microgrid-ready' enables the U.S. DoD, other federal agencies, and the private sector to plan future microgrid initiatives to utilize solar PV as a generating resource. This fact sheet provides background information with suggested language for several up-front considerations that can be added to a solar project procurement or request for proposal (RFP) that will help ensure that PV systems are built for future microgrid connection.

for Local Governments Nationwide | Department of Energy Integrating Solar PV into Energy Services Performance Contracts: Options for Local Governments Nationwide Integrating Solar PV into Energy Services Performance Contracts: Options for Local Governments Nationwide The guide contains several helpful resources, including a comprehensive list of the economic, operational, resilience, and sustainability-related benefits of entering into a performance contract and using that contract to invest

California regulators recently approved a plan proposed by Southern California Edison (SCE) to install 500 MW of distributed photovoltaic (PV) energy in its utility service territory over the next 5 years. The installations will include 250 MW of utility-owned solar and 250 MW of independently owned solar. SCE expects that the majority of these systems will be commercial-scale rooftop PV systems connected at various points in the distribution system. Each of the SCE rooftop PV systems will typically have a rating of 1-3 MW. To understand the impact of high-penetration PV on the distribution grid, the National Renewable Energy Laboratory (NREL) and SCE brought together a team of experts in resource assessment, distribution modeling, and planning to help analyze the impacts of adding high penetration of PV into the distribution system. Through modeling and simulation, laboratory testing, and field demonstrations, the team will address the issues identified in the analysis by fully examining the challenges, developing solutions, and transitioning those solutions to the field for large-scale deployment. This paper gives an update on the project and discusses technical results of integrating a large number of distributed PV systems into the grid.

As the PV industry matures, successful risk management practices will become more imperative to ensure investor confidence, control costs, and facilitate further growth. This report discusses several key aspects of risk management during the commercial- and utility-scale project life cycle, from identification of risks, to the process of mitigating and allocating those risks among project parties, to transferring those risks through insurance. The report also explores novel techniques in PV risk management, options to offload risks onto the capital markets, and innovative insurance policies (namely warranty policies) that address risks unique to the PV sector. One of the major justifications for robust risk management in the PV industry is the cost-reduction opportunities it affords. If the PV industry can demonstrate the capability to successfully manage its risks, thereby inspiring confidence in financiers, it may be able to obtain a lower cost of capital in future transactions. A lower cost of capital translates to a lower cost of energy, which will in turn enhance PV?s competitiveness at a time when it will have to rely less on subsidies to support its market penetration.

Safety is a prime concern for the photovoltaics (PV) industry. As a technology deployed on residential and commercial buildings, it is critical that PV not cause damage to the buildings nor harm the occupants. Many of the PV systems on buildings are of sufficiently high voltage (300 to 600 Volts dc) that they may present potential hazards. These PV systems must be safe in terms of mechanical damage (nothing falls on someone), shock hazard (no risk of electrical shock when touching an exposed circuit element), and fire (the modules neither cause nor promote a fire). The present safety standards (IEC 61730 and UL 1703) do a good job of providing for design rules and test requirements for mechanical, shock, and spread of flame dangers. However, neither standard addresses the issue of electrical arcing within a module that can cause a fire. To make PV modules, they must be designed, built, and installed with an emphasis on minimizing the potential for open circuits and ground faults. This paper provides recommendations on redundant connection designs, robust mounting methods, and changes to the safety standards to yield safer PV modules.

This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

Solar ADEPT Project: PV inverters convert DC power generated by modules into usable AC power. IPCs initial 30kW 94lb. PV inverter reduces the weight of comparable 30kW PV inverters by 90%reducing the cost of materials, manufacturing, shipping, and installation. With ARPA-E support, new bi-directional silicon power switches will be developed, commercialized, and utilized in IPCs next-generation PV inverter. With these components, IPC will produce 100kW inverters that weight less than 100lb., reducing the weight of conventional 3,000lb. 100kW inverters by more than 95%. The new power switches will cut IPCs $/W manufacturing cost in half, as well as further reduce indirect shipping and installation costs.

Energy Raising the Bar for Quality PV Modules EERE Success Story-Raising the Bar for Quality PV Modules October 30, 2014 - 4:58pm Addthis As photovoltaics (PV) markets expand across the United States the manufacture of safe, reliable, and high-quality PV modules is critical to achieve cost competitive solar energy. Since the development and codification of testing standards for PV modules requires a lengthy multiyear process, Department of Energy's SunShot Initiative and National Renewable

The irradiance fluctuations and the subsequent variability of the power output of a PV system are analysed with some mathematical tools based on the wavelet transform. It can be shown that the irradiance and power time series are nonstationary process whose behaviour resembles that of a long memory process. Besides, the long memory spectral exponent {alpha} is a useful indicator of the fluctuation level of a irradiance time series. On the other side, a time series of global irradiance on the horizontal plane can be simulated by means of the wavestrapping technique on the clearness index and the fluctuation behaviour of this simulated time series correctly resembles the original series. Moreover, a time series of global irradiance on the inclined plane can be simulated with the wavestrapping procedure applied over a signal previously detrended by a partial reconstruction with a wavelet multiresolution analysis, and, once again, the fluctuation behaviour of this simulated time series is correct. This procedure is a suitable tool for the simulation of irradiance incident over a group of distant PV plants. Finally, a wavelet variance analysis and the long memory spectral exponent show that a PV plant behaves as a low-pass filter. (author)

PV hybrid electric power systems can offer an economically competitive alternative to engine generator (genset) systems in many off-grid applications. Besides the obvious `green` advantages of producing less noise and emissions, the PV hybrid can, in some cases, offer a lower life-cycle cost (LCC) then the genset. This paper evaluates the LCC of the 9.6 kWp PV hybrid power system installed by the National Park Services (NPS) at Pinnacles National Monument, CA. NPS motivation for installation of this hybrid was not based on economics, but rather the need to replace two aging diesel gensets with an alternative that would be quieter, fuel efficient, and more in keeping with new NPS emphasis on sustainable design and operations. In fact, economic analysis shows a lower 20-year LCC for the installed PV hybrid than for simple replacement of the two gensets. The analysis projects are net savings by the PV hybrid system of $83,561 and over 162,000 gallons of propane when compared with the genset-only system. This net savings is independent of the costs associated with environmental emissions. The effects of including emissions costs, according to NPS guidelines, is also discussed. 5 refs., 2 figs., 3 tabs.

We examine the potential for geographic smoothing of solar photovoltaic (PV) electricity generation using 13 months of observed power production from utility-scale plants in Gujarat, India. To our knowledge, this is the first published analysis of geographic smoothing of solar PV using actual generation data at high time resolution from utility-scale solar PV plants. We use geographic correlation and Fourier transform estimates of the power spectral density (PSD) to characterize the observed variability of operating solar PV plants as a function of time scale. Most plants show a spectrum that is linear in the logâlog domain at high frequencies f,moreÂ Â» ranging from f-1.23 to f-1.56 (slopes of -1.23 and -1.56), thus exhibiting more relative variability at high frequencies than exhibited by wind plants. PSDs for large PV plants have a steeper slope than those for small plants, hence more smoothing at short time scales. Interconnecting 20 Gujarat plants yields a f-1.66 spectrum, reducing fluctuations at frequencies corresponding to 6 h and 1 h by 23% and 45%, respectively. Half of this smoothing can be obtained through connecting 4-5 plants; reaching marginal improvement of 1% per added plant occurs at 12-14 plants. The largest plant (322 MW) showed an f-1.76 spectrum. Furthermore, this suggests that in Gujarat the potential for smoothing is limited to that obtained by one large plant.Â«Â less

It is shown that for accurate testing of PV panels the correct selection of reference modules is important. A detailed description of the test methodology is given. Three different types of reference modules, having different I{sub SC} (short circuit current) and power (in Wp) have been used for this study. These reference modules have been calibrated from NREL. It has been found that for accurate testing, both I{sub SC} and power of the reference module must be either similar or exceed to that of modules under test. In case corresponding values of the test modules are less than a particular limit, the measurements may not be accurate. The experimental results obtained have been modeled by using simple equivalent circuit model and associated I-V equations. (author)

The performance of PV cells and modules with respect to standard reference conditions is a key indicator of progress of a given technology. This task provides the U.S. terrestrial PV community with the most accurate measurements that are technically possible in a timely fashion. The international module certification and accreditation program PVGap requires certification laboratories to maintain their calibration traceability path to groups like this one. The politics of a "world record" efficiency requires that an independent laboratory perform these measurements for credibility. Most manufacturers base their module peak watt rating upon standards and reference cells calibrated under this task. This task has been involved in reconciling disputes between manufacturers and their cell suppliers in terms of expected versus actual performance. This task has also served as a resource to the PV community for consultation on solar simulation, current versus voltage measurement instrumentation, measurement procedures and measurement artifacts.

With rising grid interconnections of solar photovoltaic (PV) systems, greater attention is being trained on lifecycle performance, reliability, and project economics. Expected to meet production thresholds over a 20-30 year timeframe, PV plants require a steady diet of operations and maintenance (O&M) oversight to meet contractual terms. However, industry best practices are only just beginning to emerge, and O&M budgetsâgiven the arrangement of the solar project value chainâappear to vary widely. Based on insights from in-depth interviews and survey research, this paper presents an overview of the utility-scale PV O&M budgeting process along with guiding rationales, before detailing perspectives on current plant upkeep activities and price points largely in the U.S. It concludes by pondering potential opportunities for improving upon existing O&M budgeting approaches in ways that can benefi t the industry at-large.

With rising grid interconnections of solar photovoltaic (PV) systems, greater attention is being trained on lifecycle performance, reliability, and project economics. Expected to meet production thresholds over a 20-30 year timeframe, PV plants require a steady diet of operations and maintenance (O&M) oversight to meet contractual terms. However, industry best practices are only just beginning to emerge, and O&M budgetsâgiven the arrangement of the solar project value chainâappear to vary widely. Based on insights from in-depth interviews and survey research, this paper presents an overview of the utility-scale PV O&M budgeting process along with guiding rationales, before detailing perspectives on current plant upkeep activities and price points largely in the U.S. It concludes by pondering potential opportunities for improving upon existing O&M budgeting approaches in ways that can benefit the industry at-large.

An extensive utilization of photovoltaics for future electricity generation and for hybrid generation of electricity and thermal energy is possible, when PV-panels are designed to become a part of the building envelope itself. Large areas are available, since roofs and facades are perfectly suited for solar energy conversion. Atlantis Energy Ltd. has developed special PV-generators which fulfill at the same time the functions and requirements of conventional building elements. In the context of different R and D projects funded by the Swiss government to implement a series of typical building integrated photovoltaic systems, Atlantis Energy Ltd was entrusted to design and build various hybrid building integrated PV-power plants, four of which are described in this paper.

Enormous progress has been made in recent years on a number of photovoltaic (PV) materials and devices in terms of conversion efficiencies. Ultrahigh-efficiency (>30{percent}) PV cells have been fabricated from gallium arsenide (GaAs) and its ternary alloys such as gallium indium phosphide (GaInP{sub 2}). The high-efficiency GaAs-based solar cells are being produced on a commercial scale, particularly for space applications. Efficiencies in the range of 18{percent} to 24{percent} have been achieved in traditional silicon-based devices fabricated from both multicrystalline and single-crystal materials. Major advances in efficiency have also been made on various thin-film solar cells based on amorphous silicon (aSi:H), copper gallium indium diselenide (CIGS), and cadmium telluride materials. This paper gives a brief overview of the recent progress in PV cell efficiencies based on these materials and devices.

Distributed photovoltaic (PV) projects must go through an interconnection study process before connecting to the distribution grid. These studies are intended to identify the likely impacts and mitigation alternatives. In the majority of the cases, system impacts can be ruled out or mitigation can be identified without an involved study, through a screening process or a simple supplemental review study. For some proposed projects, expensive and time-consuming interconnection studies are required. The challenges to performing the studies are twofold. First, every study scenario is potentially unique, as the studies are often highly specific to the amount of PV generation capacity that varies greatly from feeder to feeder and is often unevenly distributed along the same feeder. This can cause location-specific impacts and mitigations. The second challenge is the inherent variability in PV power output which can interact with feeder operation in complex ways, by affecting the operation of voltage regulation and protection devices. The typical simulation tools and methods in use today for distribution system planning are often not adequate to accurately assess these potential impacts. This report demonstrates how quasi-static time series (QSTS) simulation and high time-resolution data can be used to assess the potential impacts in a more comprehensive manner. The QSTS simulations are applied to a set of sample feeders with high PV deployment to illustrate the usefulness of the approach. The report describes methods that can help determine how PV affects distribution system operations. The simulation results are focused on enhancing the understanding of the underlying technical issues. The examples also highlight the steps needed to perform QSTS simulation and describe the data needed to drive the simulations. The goal of this report is to make the methodology of time series power flow analysis readily accessible to utilities and others responsible for evaluating

This report describes technical opportunities to serve as parts of a technological roadmap for Shoals Technologies Group in power electronics for PV applications. There are many different power converter circuits that can be used for solar inverter applications. The present applications do not take advantage of the potential for using common modules. We envision that the development of a power electronics module could enable higher reliability by being durable and flexible. Modules would have fault current limiting features and detection circuits such that they can limit the current through the module from external faults and can identify and isolate internal faults such that the remaining modules can continue to operate with only minimal disturbance to the utility or customer. Development of a reliable, efficient, low-cost, power electronics module will be a key enabling technology for harnessing more power from solar panels and enable plug and play operation. Power electronics for computer power supplies, communication equipment, and transportation have all targeted reliability and modularity as key requirements and have begun concerted efforts to replace monolithic components with collections of common smart modules. This is happening on several levels including (1) device level with intelligent control, (2) functional module level, and (3) system module. This same effort is needed in power electronics for solar applications. Development of modular units will result in standard power electronic converters that will have a lower installed and operating cost for the overall system. These units will lead to increased adaptability and flexibility of solar inverters. Incorporating autonomous fault current limiting and reconfiguration capabilities into the modules and having redundant modules will lead to a durable converter that can withstand the rigors of solar power generation for more than 30 years. Our vision for the technology roadmap is that there is no need

In this paper, we review the latest developments in the area of printing technologies with an emphasis on the fabrication of control-embedded photovoltaics (PV) with on-board active and passive devices. We also review the use of power converters and maximum power point tracking (MPPT) circuits with PV panels. Our focus is on the investigation of the simplest implementations of such circuits in view of their integration with solar cells using printing technologies. We see this concept as potentially enabling toward further cost reduction. Besides a discussion as to feasibility, we shall also present some projections and guidelines toward possible integration. (author)

Before investing in a system, a prospective PV customer must not only have initial concept 'buy in,' but also be able to evaluate the tradeoffs associated with different system parameters. Prospective customers might need to evaluate disparate costs for each system attribute by comparing multiple bids. The difficulty of making such an evaluation with limited information can create a cognitive barrier to proceeding with the investment. This analysis leverages recently available data from EnergySage, an online solar marketplace, to offer the first data-driven characterization of quote variation faced by prospective PV customers, lending early insight into the decisions customers face once they have initial buy-in.

1366 Technologiesâ Project Silicon addresses two of the major goals of the DOEâs PV Manufacturing Initiative Part 2 program: 1) How to reclaim a strong silicon PV manufacturing presence and; 2) How to lower the levelized cost of electricity (âLCOEâ) for solar to $0.05-$0.07/kWh, enabling wide-scale U.S. market adoption. To achieve these two goals, US companies must commercialize disruptive, high-value technologies that are capable of rapid scaling, defensible from foreign competition, and suited for US manufacturing. These are the aims of 1366 Technologies Direct Wafer âą process.

Photovoltaic (PV) module degradation rate analysis quantifies the loss of PV power output over time and is useful for estimating the impact of degradation on the cost of energy. An understanding of the degradation of all current-voltage (I-V) parameters helps to determine the cause of the degradation and also gives useful information for the design of the system. This study reports on data collected from 12 distinct mono- and poly-crystalline modules deployed at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. Most modules investigated showed < 0.5%/year decrease in maximum power due to short-circuit current decline.

Readily accessible credit has often been cited as a necessary ingredient to open up the market for residential photovoltaic (PV) systems. Though financing does not reduce the high up-front cost of PV, by spreading that cost over some portion of the system's life, financing can certainly make PV systems more affordable. As a result, a number of states have, in the past, set up special residential loan programs targeting the installation of renewable energy systems and/or energy-efficiency improvements and often featuring low interest rates, longer terms and no-hassle application requirements. Historically, these loan programs have had mixed success (particularly for PV), for a variety of reasons, including a historical lack of homeowner interest in PV, a lack of program awareness, a reduced appeal in a low-interest-rate environment, and a tendency for early PV adopters to be wealthy and not in need of financing. Some of these barriers have begun to fade. Most notably, homeowner interest in PV has grown in some states, particularly those that offer solar rebates. The passage of the Energy Policy Act of 2005 (EPAct 2005), however, introduced one additional roadblock to the success of low-interest PV loan programs: a residential solar investment tax credit (ITC), subject to the Federal government's 'anti-double-dipping' rules. Specifically, the residential solar ITC--equal to 30% of the system's tax basis, capped at $2000--will be reduced or offset if the system also benefits from what is known as 'subsidized energy financing', which is likely to include most government-sponsored low-interest loan programs. Within this context, it has been interesting to note the recent flurry of announcements from a number of U.S cities concerning a new type of PV financing program. Led by the city of Berkeley, Calif., these cities propose to offer their residents the ability to finance the installation of a PV system using increased property tax assessments, rather than a more

Photovoltaic (PV) module I-V curves were measured at Florida, Colorado, and Oregon locations to provide data for the validation and development of models used for predicting the performance of PV modules.

Photovoltaic (PV) modules have dramatically decreased in price in the past few years, spurring the expansion of photovoltaic deployment. Residential and commercial rooftop installations are connected to the distribution network; large-scale installation PV power plants (PVPs) have benefited from tax incentives and the low cost of PV modules. As the level penetration of PV generation increases, the impact on power system reliability will also be greater. Utility power system planners must consider the role of PV generation in power systems more realistically by representing PV generation in dynamic stability analyses. Dynamic models of PV inverters have been developed in the positive sequence representation. NREL has developed a PV inverter dynamic model in PSCAD/EMTDC. This paper validates the dynamic model with an actual hardware bench test conducted by Southern California Edison's Distributed Energy Resources laboratory. All the fault combinations -- symmetrical and unsymmetrical -- were performed in the laboratory. We compare the simulation results with the bench test results.

Operations | Department of Energy Integration of Behind-the-Meter PV Fleet Forecasts into Utility Grid System Operations Integration of Behind-the-Meter PV Fleet Forecasts into Utility Grid System Operations Clean Power Research logo.jpg This project will address the need for a more accurate approach to forecasting net utility load by taking into consideration the contribution of customer-sited PV energy generation. Tasks within the project are designed to integrate novel PV power

of Energy Literature Review of the Effects of UV Exposure on PV Modules Literature Review of the Effects of UV Exposure on PV Modules This PowerPoint presentation, originally presented at the NREL 2013 PV Module Reliability Workshop on Feb. 26-27, 2013 in Denver, CO, presents the literature review of the effects of prolonged UV exposure of PV modules, with a particular emphasis on UV exposure testing using artificial light sources, including fluorescent, Xenon, and metal halide lamps.

While solar PV's impact on utilities has been frequently discussed the past year, little attention has been paid to the potentially impact posed by solar PV-specific rate designs (often informally referred to as solar "fees" or "taxes") upon non-hardware "soft" cost reductions. In fact, applying some rate designs to solar PV customers could potentially have a large impact on the economics of PV systems.

Sandia/EPRI PV Symposium - Save the Date! Save the Date and Call for Abstracts Sandia-EPRI 2016 PV Systems Symposium May 9-11 th at the Biltmore Hotel in Santa Clara, CA Sandia National Laboratories (SNL) and the Electric Power Research Institute (EPRI) are delighted to host this symposium on the technical challenges and opportunities related to solar photovoltaic (PV) systems and technologies. Core areas of focus will include PV performance modeling, distribution hosting capacity and screening

Energy Modeling and Analysis of High-Penetration PV in California Modeling and Analysis of High-Penetration PV in California NREL logo.jpg The NREL project team will utilize field verification to improve the ability to model and understand the impacts of high-penetration PV on electric utility systems and develop solutions to ease high-penetration PV deployments. The team will develop and verify advanced modeling and simulation methods for distribution system planning and operations; define

The presentation describes the value of adding DC converters and other power electronics to modules to improve their output even when shading or bad cells would otherwise decrease the module output. The presentation was part of a workshop sponsored by ARPA-E exploring the opportunities for power electronics to support PV applications.

This analysis leverages available data from EnergySage, an online solar marketplace, to offer the first data-driven characterization of quote variation faced by prospective PV customers, lending early insight into the decisions customers face once they have initial buy-in.

EERE's Solar Energy Technologies Program is charged with leading the Secretary's SunShot Initiative to reduce the cost of electricity from solar by 75% to be cost competitive with conventional energy sources without subsidy by the end of the decade. As part of this Initiative, the program has funded the National Renewable Energy Laboratory (NREL) to develop module manufacturing and solar PV system installation cost models to ensure that the program's cost reduction targets are carefully aligned with current and near term industry costs. The NREL cost analysis team has leveraged the laboratories' extensive experience in the areas of project finance and deployment, as well as industry partnerships, to develop cost models that mirror the project cost analysis tools used by project managers at leading U.S. installers. The cost models are constructed through a "bottoms-up" assessment of each major cost element, beginning with the system's bill of materials, labor requirements (type and hours) by component, site-specific charges, and soft costs. In addition to the relevant engineering, procurement, and construction costs, the models also consider all relevant costs to an installer, including labor burdens and overhead rates, supply chain costs, and overhead and materials inventory costs, and assume market-specific profits.

This draft report summarizes the results of the U.S. Department of Energy PV Manufacturing Request for Information (RFI), DE-FOA-0000153, that was released in September 2009. The PV Manufacturing Initiative is intended to help facilitate the development of a strong PV manufacturing industry in the United States.

Distributed Solar PV systems have the potential of increasing the grid's resiliency to unforeseen events, such as extreme weather events and attacks. This paper presents the role that distributed PV can play in electric grid resiliency, introduces basic system design requirements and options, and discusses the regulatory and policy options for supporting the use of distributed PV for the purpose of increased electricity resiliency.

The power output variability of photovoltaic systems can affect local electrical grids in locations with high renewable energy penetrations or weak distribution or transmission systems. In those rare cases, quick controllable generators (e.g., energy storage systems) or loads can counteract the destabilizing effects by compensating for the power fluctuations. Previously, control algorithms for coordinated and uncoordinated operation of a small natural gas engine-generator (genset) and a battery for smoothing PV plant output were optimized using MATLAB/Simulink simulations. The simulations demonstrated that a traditional generation resource such as a natural gas genset in combination with a battery would smooth the photovoltaic output while using a smaller battery state of charge (SOC) range and extending the life of the battery. This paper reports on the experimental implementation of the coordinated and uncoordinated controllers to verify the simulations and determine the differences in the controllers. The experiments were performed with the PNM PV and energy storage Prosperity site and a gas engine-generator located at the Aperture Center at Mesa Del Sol in Albuquerque, New Mexico. Two field demonstrations were performed to compare the different PV smoothing control algorithms: (1) implementing the coordinated and uncoordinated controls while switching off a subsection of the PV array at precise times on successive clear days, and (2) comparing the results of the battery and genset outputs for the coordinated control on a high variability day with simulations of the coordinated and uncoordinated controls. It was found that for certain PV power profiles the SOC range of the battery may be larger with the coordinated control, but the total amp-hours through the battery-which approximates battery wear-will always be smaller with the coordinated control.

We examine the potential for geographic smoothing of solar photovoltaic (PV) electricity generation using 13 months of observed power production from utility-scale plants in Gujarat, India. To our knowledge, this is the first published analysis of geographic smoothing of solar PV using actual generation data at high time resolution from utility-scale solar PV plants. We use geographic correlation and Fourier transform estimates of the power spectral density (PSD) to characterize the observed variability of operating solar PV plants as a function of time scale. Most plants show a spectrum that is linear in the logâlog domain at high frequencies f, ranging from f-1.23 to f-1.56 (slopes of -1.23 and -1.56), thus exhibiting more relative variability at high frequencies than exhibited by wind plants. PSDs for large PV plants have a steeper slope than those for small plants, hence more smoothing at short time scales. Interconnecting 20 Gujarat plants yields a f-1.66 spectrum, reducing fluctuations at frequencies corresponding to 6 h and 1 h by 23% and 45%, respectively. Half of this smoothing can be obtained through connecting 4-5 plants; reaching marginal improvement of 1% per added plant occurs at 12-14 plants. The largest plant (322 MW) showed an f-1.76 spectrum. Furthermore, this suggests that in Gujarat the potential for smoothing is limited to that obtained by one large plant.

This paper describes a field demonstration that was completed to show the ability of currently installed PV inverters to implement advanced PV inverter functionality and that such functionality was effective at reducing the voltage-related PV impacts of high-penetration PV integration. A distribution circuit was instrumented and then tested for a two week period using off-unity power factor operation. Specifically, an inductive power factor of -0.95 was demonstrated. The results show that the PV inverters were capable of such operation and that the use of off-unity power factor operation was highly effective at reducing the voltage-related impacts of the PV systems interconnected to the circuits used in the demonstration. The impacts of using off-unity power factor operation - resulting in additional reactive current flow on the distribution circuit - are also presented and analyzed.

Southern California Edison (SCE) is well into a five-year project to install a total of 500 MW of distributed photovoltaic (PV) energy within its utility service territory. Typical installations to date are 1-3 MW peak rooftop PV systems that interconnect to medium-voltage urban distribution circuits or larger (5 MW peak) ground-mounted systems that connect to medium-voltage rural distribution circuits. Some of the PV system interconnections have resulted in distribution circuits that have a significant amount of PV generation compared to customer load, resulting in high-penetration PV integration scenarios. The National Renewable Energy Laboratory (NREL) and SCE have assembled a team of distribution modeling, resource assessment, and PV inverter technology experts in order to investigate a few of the high-penetration PV distribution circuits. Currently, the distribution circuits being studied include an urban circuit with a PV penetration of approximately 46% and a rural circuit with a PV penetration of approximately 60%. In both cases, power flow on the circuit reverses direction, compared to traditional circuit operation, during periods of high PV power production and low circuit loading. Research efforts during year two of the five-year project were focused on modeling the distribution system level impacts of high-penetration PV integrations, the development and installation of distribution circuit data acquisition equipment appropriate for quantifying the impacts of high-penetration PV integrations, and investigating high-penetration PV impact mitigation strategies. This paper outlines these research efforts and discusses the following activities in more detail: the development of a quasi-static time-series test feeder for evaluating high-penetration PV integration modeling tools; the advanced inverter functions being investigated for deployment in the project's field demonstration and a power hardware-in-loop test of a 500-kW PV inverter implementing a

The SunShot Vision Study explored the potential growth of solar markets if solar prices decreased by about 75% from 2010 to 2020. The SolarDS model was used to simulate rooftop PV demand for this study, based on several PV market assumptions--future electricity rates, customer access to financing, and others--in addition to the SunShot PV price projections. This paper finds that modeled PV demand is highly sensitive to several non-price market assumptions, particularly PV financing parameters.

Going Solar in Record Time with Plug-and-Play PV Going Solar in Record Time with Plug-and-Play PV April 24, 2012 - 6:10pm Addthis A plug-and-play PV system is envisioned as a consumer friendly solar technology that uses an automatic detection system to initiate communication between the solar energy system and the utility when plugged into a PV-ready circuit. | Photo by iStock. A plug-and-play PV system is envisioned as a consumer friendly solar technology that uses an automatic detection system

The U.S. photovoltaic (PV) industry is forecast to grow, and it represents an opportunity for economic development and job creation in communities throughout the United States. This report helps U.S. cities evaluate economic opportunities in the PV industry. It serves as a guide for local economic development offices in evaluating their community?s competitiveness in the solar PV industry, assessing the viability of solar PV development goals, and developing strategies for recruiting and retaining PV companies to their areas.

For those PV technologies that rely upon Te, In, and Ga, first-order observations and calculations hint that there may be resource constraints that could inhibit their successful deployment at a SunShot level. These are only first-order approximations, however, and the possibility for an expansion in global Te, In, and Ga supplies needs to be considered in the event that there are upward revisions in their demand and prices.In this study, we examine the current, mid-term, and long-term prospects of Tellurium (Te) for use in PV. We find that the current global supply base of Te would support <10 GW of annual traditional CdTe PV manufacturing production. But as for the possibility that the supply base for Te might be expanded, after compiling several preliminary cumulative availability curves we find that there may be significant upside potential in the supply base for this element - principally vis a vis increasing demand and higher prices. Primarily by reducing the Tellurium intensity in manufacturing and by increasing the recovery efficiency of Te in Cu refining processes, we calculate that it may prove affordable to PV manufacturers to expand the supply base for Te such that 100 GW, or greater, of annual CdTe PV production is possible in the 2030 - 2050 timeframe.

Photoluminescence (PL) imaging is widely used to identify defective regions within mc-Si PV cells. Recent PL imaging investigations of defect band luminescence (DBL) in mc-Si have revealed a perplexing phenomenon. Namely, the reversal of the DBL intensity in various regions of mc-Si PV material upon the application of a SiNx:H anti-reflective coating (ARC). Regions with low DBL intensity before ARC application often exhibit high DBL intensity afterwards, and the converse is also true. PL imaging alone cannot explain this effect. We have used high resolution cathodoluminescence (CL) spectroscopy and electron beam induced current (EBIC) techniques to elucidate the origin of the DBL intensity reversal. Multiple sub-bandgap energy levels were identified that change in peak position and intensity upon the application of the ARC. Using this data, in addition to EBIC contrast information, we provide an explanation for the DBL intensity reversal based on the interaction of the detected energy levels with the SiNx:H ARC application. Multiple investigations have suggested that this is a global problem for mc-Si PV cells. Our results have the potential to provide mc-Si PV producers a pathway to increased efficiencies through defect mitigation strategies.

This handbook has been developed as part of a five-year research project which began in 2010. The National Renewable Energy Laboratory (NREL), Southern California Edison (SCE), Quanta Technology, Satcon Technology Corporation, Electrical Distribution Design (EDD), and Clean Power Research (CPR) teamed together to analyze the impacts of high-penetration levels of photovoltaic (PV) systems interconnected onto the SCE distribution system. This project was designed specifically to leverage the experience that SCE and the project team would gain during the significant installation of 500 MW of commercial scale PV systems (1-5 MW typically) starting in 2010 and completing in 2015 within SCEâs service territory through a program approved by the California Public Utility Commission (CPUC).

The economic viability of photovoltaic (PV) technologies is inextricably tied to both the electrical performance and degradation rate of the PV systems, which are the generators of electrical power in PV systems. Over the past 15 years, performance data have been collected on numerous PV systems installed throughout the state of Florida and will be presented.

Brochure highlighting NREL's partnership with SolarCity and Hawaiian Electric (HECO) to increase the penetration of solar photovoltaics on the electricity grid. To better understand the potential impact of transient overvoltages due to load rejection, NREL collaborated with SolarCity and HECO to run a series of tests measuring the magnitude and duration of load rejection overvoltage events and demonstrating the ability of advanced PV inverters to mitigate their impacts.

Provides PV Holiday Lights for Christmas Tree For more information contact: George Douglas (303) 275-4096 Golden, Colo., December 2, 1997 -- National Renewable Energy Laboratory (NREL) engineers are showing off the power of photovoltaics in Washington, D.C. again this holiday season. They have installed an 8-kilowatt solar array on the Ellipse just south of the White House to help power lights on the National Christmas Tree. The tree lighting ceremony on Dec. 4 begins Washington's 1997 Pageant

Request Proposals for Reducing PV Costs For more information contact: George Douglas, (303) 275-4096 Golden, Colo., May 15, 1997 -- The U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) invites the photovoltaics and related industries to join its Photovoltaic Manufacturing Technology (PVMaT) program in looking for ways to improve production processes and reduce the cost of photovoltaic products. NREL will issue in the next 90 days an $8 million request for proposals

technologies - Energy Innovation Portal Find More Like This Return to Search Voltage-matched multijunction solar cell architectures for integrating PV technologies National Renewable Energy Laboratory Contact NREL About This Technology Technology Marketing Summary The U.S. Department of Energy SunShot Initiative aims to reduce the total installed cost of solar energy systems to $.06 per kilowatt-hour (kWh) by the year 2020. Reducing the cost of solar electricity requires that solar cell

Screening Procedures and Online Tools Page 1 of 9 Kristen Ardani, Joel Dickinson, Max Berger, David Crowell, Jeff Dickinson, Kelly Webster Page 1 of 9 [Speaker: Kristen Ardani] Cover Slide: Thank you everyone for joining us today for the DG Interconnection Collaborative. My name is Kristen Ardani,I'm an analyst here at NREL and the lead facilitator of the DGIC. We are fortunate today to have speakers Joel Dickinson of Salt River Project. We are going to discuss distributed PV interconnection

NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable Energy Operated by the Alliance for Sustainable Energy, LLC This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Contract No. DE-AC36-08GO28308 High-Penetration PV Integration Handbook for Distribution Engineers Rich Seguin, Jeremy Woyak, David Costyk, and Josh Hambrick Electrical Distribution Design Barry Mather National

Utility Participation in the Rooftop Solar PV Market Page 1 of 21 Kristen Ardani, Jurstin Orkney, Marc Romito Page 1 of 21 [Speaker: Kristen Ardani] Slide 1: Good afternoon, everyone. Thank you for joining the Distributed Generation Interconnection Collaborative Monthly Informational Webinar. My name is Kristen Ardani, and I'm an analyst here at NREL and the moderator for the DGIC. So today, we are kicking off 2016 with a joint presentation from two Arizona utilities that have implemented

PG&E has developed a plan to install 500 MW of PV by the year 2015. The plan calls for 250 MW to be acquired through Power Purchase Agreements (PPA) and the other 250 MW to be purchased and owned by the utility. PG&E presented the plan at a public forum on April 27, 2009. A copy of the power point presentation is attached.

A building-integrated multifunctional PV/T solar window has been developed and evaluated. It is constructed of PV cells laminated on solar absorbers placed in a window behind the glazing. To reduce the cost of the solar electricity, tiltable reflectors have been introduced in the construction to focus radiation onto the solar cells. The reflectors render the possibility of controlling the amount of radiation transmitted into the building. The insulated reflectors also reduce the thermal losses through the window. A model for simulation of the electric and hot water production was developed. The model can perform yearly energy simulations where different features such as shading of the cells or effects of the glazing can be included or excluded. The simulation can be run with the reflectors in an active, up right, position or in a passive, horizontal, position. The simulation program was calibrated against measurements on a prototype solar window placed in Lund in the south of Sweden and against a solar window built into a single family house, Solgaarden, in Aelvkarleoe in the central part of Sweden. The results from the simulation shows that the solar window annually produces about 35% more electric energy per unit cell area compared to a vertical flat PV module. (author)

The purpose of this presentation is to provide a brief introduction to measurement uncertainty analysis, outline how it is done, and illustrate uncertainty analysis with examples drawn from the PV field, with particular emphasis toward its use in PV performance measurements. The uncertainty information we know and state concerning a PV performance measurement or a module test result determines, to a significant extent, the value and quality of that result. What is measurement uncertainty analysis It is an outgrowth of what has commonly been called error analysis. But uncertainty analysis, a more recent development, gives greater insight into measurement processes and tests, experiments, or calibration results. Uncertainty analysis gives us an estimate of the I interval about a measured value or an experiment's final result within which we believe the true value of that quantity will lie. Why should we take the time to perform an uncertainty analysis A rigorous measurement uncertainty analysis: Increases the credibility and value of research results; allows comparisons of results from different labs; helps improve experiment design and identifies where changes are needed to achieve stated objectives (through use of the pre-test analysis); plays a significant role in validating measurements and experimental results, and in demonstrating (through the post-test analysis) that valid data have been acquired; reduces the risk of making erroneous decisions; demonstrates quality assurance and quality control measures have been accomplished; define Valid Data as data having known and documented paths of: Origin, including theory; measurements; traceability to measurement standards; computations; uncertainty analysis of results.

This CESA - LBNL Case Study examines how much economic value do new and expanded federal tax credits really provide to PV system purchasers, and what implications might they hold for state/utility PV grant programs. The report begins with a discussion of the taxability of PV grants and their interaction with federal credits, as this issue significantly affects the analysis that follows. We then calculate the incremental value of EPAct's new and expanded credits for PV systems of different sizes, and owned by different types of entities. The report concludes with a discussion of potential implications for purchasers of PV systems, as well as for administrators of state/utility PV programs. The market for grid-connected photovoltaics (PV) in the US has grown dramatically in recent years, driven in large part by PV grant or 'buy-down' programs in California, New Jersey, and many other states. The recent announcement of a new 11-year, $3.2 billion PV program in California suggests that state policy will continue to drive even faster growth over the next decade. Federal policy has also played a role, primarily by providing commercial PV systems access to tax benefits, including accelerated depreciation (5-year MACRS schedule) and a business energy investment tax credit (ITC). Since the signing of the Energy Policy Act of 2005 (EPAct) on August 8, the federal government has begun to play a much more significant role in supporting both commercial and residential PV systems. Specifically, EPAct increased the federal ITC for commercial PV systems from 10% to 30% of system costs, and also created a new 30% ITC (capped at $2000) for residential solar systems. Both changes went into effect on January 1, 2006, for an initial period of two years, and in late 2006 were extended for an additional year. Unless extended further, the new residential ITC will expire, and the 30% commercial ITC will revert back to 10%, on January 1, 2009. How much economic value do these new and

Increasing levels of financial support for customer-sited photovoltaic (PV) systems, provided through publicly-funded incentive programs, has heightened concerns about the long-term performance of these systems. Given the barriers that customers face to ensuring that their PV systems perform well, and the responsibility that PV incentive programs bear to ensure that public funds are prudently spent, these programs should, and often do, play a critical role in ensuring that PV systems receiving incentives perform well. To provide a point of reference for assessing the current state of the art, and to inform program design efforts going forward, we examine the approaches to encouraging PV system performance used by 32 prominent PV incentive programs in the U.S. We identify eight general strategies or groups of related strategies that these programs have used to address performance issues, and highlight important differences in the implementation of these strategies among programs.

Property Assessed Clean Energy (PACE) financing is one of several new financial models broadening access to clean energy by addressing the barrier of initial capital cost. The majority of the PACE programs in the market today include PV as an eligible measure. PV appeals to homeowners as a way to reduce utility bills, self-generate sustainable power, increase energy independence and demonstrate a commitment to the environment. If substantial state incentives for PV exist, PV projects can be economic under PACE, especially when partnered with good net metering policies. At the same time, PV is expensive relative to other eligible measures with a return on investment horizon that might exceed program targets. This fact sheet reviews the benefits and potential challenges of including PV in PACE programs.

NREL Solar Researcher Honored with World PV Award May 10, 2006 Golden, Colo. - Dr. Lawrence Kazmerski, a leading research director at the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL), received the World PV Award at the Fourth World Conference on Photovoltaic Energy Conversion on May 9 for his outstanding contributions to the worldwide advancements of photovoltaic (PV) science and technology. The award, sponsored by professional organizations from the European,

for Solar Deployment - News Releases | NREL Supports China PV Investment and Financing Alliance to Open Capital for Solar Deployment May 14, 2015 The Energy Department's National Renewable Energy Laboratory (NREL) and the China PV Investment and Finance Alliance (CPVFA) have formed a collaboration with the goal of opening wide-scale and diverse sources of investment for solar photovoltaic (PV) asset development in China. NREL is advising CPVFA based on the work of the NREL-convened Solar

In 1995, the NREL/Department of Energy (DOE) National Photovoltaics Program funded seven Historically Black Colleges and Universities (HBCUs) in its HBCU Photovoltaic Research Associates Program for a period of three years. The program's purpose is to advance HBCU undergraduate knowledge of photovoltaics, primarily as a result of research investigations performed, and to encourage students to pursue careers in photovoltaics. This paper presents results from PV projects ranging from fundamental materials research on PV materials to field projects of PV systems.

| Department of Energy Impacts of High Penetration of PV with Energy Storage at Flagstaff Arizona Impacts of High Penetration of PV with Energy Storage at Flagstaff Arizona aps-logo.gif --This project is inactive -- The project team, led by Arizona Public Service, will evaluate the impacts of high penetrations of distributed PV and energy storage on a dedicated feeder to identify the technical and operational modifications that could be deployed in future feeder designs. APPROACH Models

The Advanced Measurement and Analysis of PV Derate Factors project focuses on improving the accuracy and reducing the uncertainty of PV performance model predictions by addressing a common element of all PV performance models referred to as âderatesâ. Widespread use of ârules of thumbâ, combined with significant uncertainty regarding appropriate values for these factors contribute to uncertainty in projected energy production.

Distribution Engineers Releases High-Penetration PV Handbook for Distribution Engineers A new resource sponsored by the Energy Department's SunShot Initiative helps distribution engineers understand the challenges of high-penetration PV integration. January 27, 2016 As solar photovoltaic (PV) systems are increasingly installed throughout the country at distribution-level utility scale, a new challenge is emerging: how to safely and effectively integrate greater amounts of variable solar

The purpose of this presentation is to provide a brief introduction to measurement uncertainty analysis, outline how it is done, and illustrate uncertainty analysis with examples drawn from the PV field, with particular emphasis toward its use in PV performance measurements. The uncertainty information we know and state concerning a PV performance measurement or a module test result determines, to a significant extent, the value and quality of that result. What is measurement uncertainty analysis? It is an outgrowth of what has commonly been called error analysis. But uncertainty analysis, a more recent development, gives greater insight into measurement processes and tests, experiments, or calibration results. Uncertainty analysis gives us an estimate of the I interval about a measured value or an experiment`s final result within which we believe the true value of that quantity will lie. Why should we take the time to perform an uncertainty analysis? A rigorous measurement uncertainty analysis: Increases the credibility and value of research results; allows comparisons of results from different labs; helps improve experiment design and identifies where changes are needed to achieve stated objectives (through use of the pre-test analysis); plays a significant role in validating measurements and experimental results, and in demonstrating (through the post-test analysis) that valid data have been acquired; reduces the risk of making erroneous decisions; demonstrates quality assurance and quality control measures have been accomplished; define Valid Data as data having known and documented paths of: Origin, including theory; measurements; traceability to measurement standards; computations; uncertainty analysis of results.

Energy Modeling and Analysis of High-Penetration PV in Florida Modeling and Analysis of High-Penetration PV in Florida caps-fsu-logo.jpg This project aims to leverage simulation-assisted research and development based on a wide variety of Florida feeders that already incorporate high levels of PV power. Working with utilities, the team at Florida State University's Center for Advanced Power Systems (FSU CAPS) will evaluate and model impacts of the effects of high-penetration PV on

Plug and Play Solar PV for American Homes Plug and Play Solar PV for American Homes logo-fraunhofer.gif The Fraunhofer Center for Sustainable Energy Systems (CSE) will develop a new plug-and-play PV system that self-checks for proper installation and safety and communicates with the local utility and local jurisdiction to request permission to feed power into its smart meter. The utility and locality will remotely grant permission to the system to connect, and the PV system will immediately

As described in Part 1 of this two-part series, thermopile pyranometers and photovoltaic (PV) reference cells can both be used to measure irradiance; however, there are subtle differences between the data that are obtained. This two-part article explores some implications of uncertainty and subtleties of accurately measuring PV efficiency in the field. Part 2 of the series shows how reference cells can be used to more confidently predict PV performance, but how this could best be accomplished if historic irradiance data could be available in PV-technology-specific formats.

Characterizing the factors that affect reliability of a photovoltaic (PV) power plant is an important aspect of optimal asset management. This document describes the many factors that affect operation and maintenance (O&M) of a PV plant, identifies the data necessary to quantify those factors, and describes how data might be used by O&M service providers and others in the PV industry. This document lays out data needs from perspectives of reliability, availability, and key performance indicators and is intended to be a precursor for standardizing terminology and data reporting, which will improve data sharing, analysis, and ultimately PV plant performance.

This conference paper describes the high moisture barrier high resistivity coatings on polyethylene terepthalate (PET) have been fabricated and characterized for use in PV module back sheet applications. These thin film barriers exhibit water vapor transmission rates (WVTR) as low as 0.1 g/m2-day at 37.8 C and have shown excellent adhesion (> 10 N/mm) to both ethylene vinyl acetate (EVA) and PET even after filtered xenon arc lamp UV exposure. The WVTR and adhesion values for this construction are compared to and shown to be superior to candidate polymeric backsheet materials.

Solar energy systems hang their hats on payback. Financial payback is as tangible as money in your bank account, while other types of paybackâlike environmental externalitiesâare not usually calculated in dollars. Thereâs no doubt that photovoltaic (PV) and solar hot water (SHW) systems will pay you back. Maybe not as quickly as youâd like, but all systems will significantly offset their cost over their lifetimes. Here weâll try to answer: Which system will give the quickest return on investment (ROI)?

Utility Participation in the Rooftop Solar PV Market DG Interconnection Collaborative (DGIC) January 21, 2016 Justin Orkney Program Manager of Distributed Generation Tucson Electric Power (TEP) Marc Romito Manager Arizona Public Service 2 Logistics * Participants are joined in listen-only mode. * Use the Q&A panel to ask questions during the webinar. We will have a few minutes of Q&A between each presentation and group discussion at the very end. ï To ask a question: o Click Q&A

Overview of the solar resource assessment conducted by the National Renewable Energy Laboratory (NREL) in cooperation with Kauai Island Utility Cooperative (KIUC) in Hawaii to determine the technical feasibility of increasing the contribution of solar renewable energy generation on the island of Kauaii through the use of photovoltaic (PV) arrays. The analysis, which was performed using a custom version of NREL's In My Back Yard (IMBY) software tool, showed that there is potential to generate enough energy to cover the peak load as reported for Kauai in 2007.

Machinist Pipeline/Apprentice Program Program Description The Machinist Pipeline Program was created by the Prototype Fabrication Division to fill a critical need for skilled journeyworker machinists. It is based on a program developed by the National Institute for Metalworking Skills (NIMS) in conjunction with metalworking trade associations to develop and maintain a globally competitive U.S. workforce. The goal is to develop and implement apprenticeship programs that are aligned with

Eventually, distributed PV will become a more significant part of the generation mix. When this happens, it is expected that utilities will have to take on a more active role in the placement, operation and control of these systems. There are operational complexities and concerns of revenue erosion that will drive utilities into greater involvement of distributed PV and will create new business models. This report summarizes work done by Navigant Consulting Inc. for the National Renewable Energy Laboratory as part of the Department of Energy's work on Renewable System Integration. The objective of the work was to better understand the structure of these future business models and the research, development and demonstration (RD&D) required to support their deployment. This report describes potential future PV business models in terms of combinations of utility ownership and control of the PV assets, and the various relationships between end-users and third-party owners.

Global Solar Energy rapidly advances the cost and performance of commercial thin-film CIGS products using roll-to-roll processing on steel foil substrate in compact, low cost deposition equipment, with in-situ sensors for real-time intelligent process control. Substantial increases in power module efficiency, which now exceed 13%, are evident at GSE factories in two countries with a combined capacity greater than 75 MW. During 2009 the average efficiency of cell strings (3780 cm2) was increased from 7% to over 11%, with champion results exceeding 13% Continued testing of module reliability in rigid product has reaffirmed extended life expectancy for standard glass product, and has qualified additional lower-cost methods and materials. Expected lifetime for PV in flexible packages continues to increase as failure mechanisms are elucidated, and resolved by better methods and materials. Cost reduction has been achieved through better materials utilization, enhanced vendor and material qualification and selection. The largest cost gains have come as a result of higher cell conversion efficiency and yields, higher processing rates, greater automation and improved control in all process steps. These improvements are integral to this thin film PV partnership program, and all realized with the 'Gen2' manufacturing plants, processes and equipment.

Photovoltaic module quality has remained high even as module prices have declined. Scientists at the National Renew- able Energy Laboratory (NREL) have analyzed the annual performance data from almost 50,000 photo- voltaic (PV) systems that total 1.7 gigawatts of capacity installed in the United States from 2009 to 2012. The overall conclusion is that the vast majority performed as expected. Since 2009, the price of PV modules has fallen dramatically-and with this drop has come concerns about

There is confusion in the marketplace regarding the impact of solar photovoltaics (PV) on the user's actual electricity bill under California Net Energy Metering, particularly with binomial tariffs (those that include both demand and energy charges) and time-of-use (TOU) rate structures. The City of San Diego has extensive real-time electrical metering on most of its buildings and PV systems, with interval data for overall consumption and PV electrical production available for multiple years. This paper uses 2007 PV-system data from two city facilities to illustrate the impacts of binomial rate designs. The analysis will determine the energy and demand savings that the PV systems are achieving relative to the absence of systems. A financial analysis of PV-system performance under various rate structures is presented. The data revealed that actual demand and energy use benefits of binomial tariffs increase in summer months, when solar resources allow for maximized electricity production. In a binomial tariff system, varying on- and semi-peak times can result in approximately $1,100 change in demand charges per month over not having a PV system in place, an approximate 30% cost savings. The PV systems are also shown to have a 30%-50% reduction in facility energy charges in 2007.

The DOE-funded Power Systems Engineering Research Center (PSERC) is offering a free public webinar presenting a simulation-based investigation of PV impacts on distribution systems and discussing a new approach for volt-VAR optimization with reactive power capabilities of PV inverters.

Article 690.11 in the 2011 National Electrical Code{reg_sign} (NEC{reg_sign}) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc fault protection device. Currently there is little experimental or empirical research into the behavior of the arcing frequencies through PV components despite the potential for modules and other PV components to filter or attenuate arcing signatures that could render the arc detector ineffective. To model AC arcing signal propagation along PV strings, the well-studied DC diode models were found to inadequately capture the behavior of high frequency arcing signals. Instead dynamic equivalent circuit models of PV modules were required to describe the impedance for alternating currents in modules. The nonlinearities present in PV cells resulting from irradiance, temperature, frequency, and bias voltage variations make modeling these systems challenging. Linearized dynamic equivalent circuits were created for multiple PV module manufacturers and module technologies. The equivalent resistances and capacitances for the modules were determined using impedance spectroscopy with no bias voltage and no irradiance. The equivalent circuit model was employed to evaluate modules having irradiance conditions that could not be measured directly with the instrumentation. Although there was a wide range of circuit component values, the complex impedance model does not predict filtering of arc fault frequencies in PV strings for any irradiance level. Experimental results with no irradiance agree with the model and show nearly no attenuation for 1 Hz to 100 kHz input frequencies.

PV reliability is a challenging topic because of the desired long life of PV modules, the diversity of use environments and the pressure on companies to rapidly reduce their costs. This presentation describes the challenges, examples of failure mechanisms that we know or don't know how to test for, and how a scientific approach is being used to establish international standards.

The ASP Program Description provides a general overview of the auditing, proficiency testing and field sampling planning activities in support of mission-critical DOE operations such as on-going environmental monitoring, environmental remediation, and long-term legacy management and surveillance of past field sites

It is often difficult to model the effects of partial shading conditions on PV array performance, as shade losses are nonlinear and depend heavily on a system's particular configuration. This work describes and implements a simple method for modeling shade loss: a database of shade impact results (loss percentages), generated using a validated, detailed simulation tool and encompassing a wide variety of shading scenarios. The database is intended to predict shading losses in crystalline silicon PV arrays and is accessed using basic inputs generally available in any PV simulation tool. Performance predictions using the database are within 1-2% of measured data for several partially shaded PV systems, and within 1% of those predicted by the full, detailed simulation tool on an annual basis. The shade loss database shows potential to considerably improve performance prediction for partially shaded PV systems.

The plan to transform the rooftop photovoltaic (PV) market in Puerto Rico strives to create not only a standardized framework for PV deployment, but also streamlined and organized, lean permitting and interconnection processes where most residential and small commercial PV systems can be installed safely and quickly. Puerto Rico has regulations and requirements that limit our ability to adopt the expedited permitting recommendations proposed by Solar ABC and the Network for New Energy Choices. It is the intent of this proposal to identify, analyze, and provide best practices that overcomes these obstacles. The final deliverable of the proposal will be a holistic framework that ensures process predictability and standardization while dealing with rooftop PV market barriers. The plan may impact all of Puerto Rico (pop. 3.7 million), and bolster the incipient PV market in the Island.

As a market segment for solar photovoltaic (PV) adoption, new homes have a number of attractive attributes. Homebuyers can easily roll the cost of the PV system into their mortgage and, with rebates or other financial incentives, potentially realize an immediate net positive cash flow from the investment. PV system performance can be optimized by taking roof orientation, shading, and other structural factors into account in the design of new homes. Building-integrated photovoltaics (BIPV), which are subject to fewer aesthetic concerns than traditional, rack-mounted systems, are well-suited to new construction applications. In large new residential developments, costs can be reduced through bulk purchases and scale economies in system design and installation. Finally, the ability to install PV as a standard feature in new developments - like common household appliances - creates an opportunity to circumvent the high transaction costs and other barriers typically confronted when each individual homeowner must make a distinct PV purchase decision.

This document outlines the foundation for developing language that can be utilized in an Equipment Availability Guarantee, typically included in an O&M services agreement between a PV system or plant owner and an O&M services provider, or operator. Many of the current PV O&M service agreement Availability Guarantees are based on contracts used for traditional power generation, which create challenges for owners and operators due to the variable nature of grid-tied photovoltaic generating technologies. This report documents language used in early PV availability guarantees and presents best practices and equations that can be used to more openly communicate how the reliability of the PV system and plant equipment can be expressed in an availability guarantee. This work will improve the bankability of PV systems by providing greater transparency into the equipment reliability state to all parties involved in an O&M services contract.

This presentation outlines the goals and specific tasks of break-out session 2 of the 2011 International PV Module Quality Assurance Forum, along with a review of accelerated stress tests used for photovoltaics (PV).

PV FOR ELECTRICITY SYSTEM RESILIENCY POLICY AND REGULATORY CONSIDERATIONS ABSTRACT Distributed solar photovoltaic (PV) systems have the potential to supply electricity during grid outages resulting from extreme weather or other emergency situations. As such, distributed PV can signifcantly increase the resiliency of the electricity system. In order to take advantage of this capability, however, the PV systems must be designed with resiliency in mind and combined with other technologies, such as

Mismatch power losses in photovoltaic (PV) systems can be reduced by the use of distributed power electronics at the module or submodule level. This paper presents an experimentally validated numerical model that can be used to predict power production with distributed maximum power point tracking (DMPPT) down to the cell level. The model allows the investigations of different DMPPT architectures, as well as the impact of conversion efficiencies and power constraints. Results are presented for annual simulations of three representative partial shading scenarios and two scenarios where mismatches are due to aging over a period of 25 years. It is shown that DMPPT solutions that are based on submodule integrated converters offer 6.9-11.1% improvements in annual energy yield relative to a baseline centralized MPPT scenario.

In September 2000, the Interstate Renewable Energy Council (IREC) began its 5-year work on contract # DE-FGO3-00SF22116, the Photovoltaics for You (PV4You) Project. The objective was to develop and distribute information on photovoltaics and to educate key stakeholder groups including state government agencies, local government offices, consumer representative agencies, school officials and students, and Million Solar Roofs Partnerships. In addition, the project was to identify barriers to the deployment of photovoltaics and implement strategies to overcome them. Information dissemination and education was accomplished by publishing newsletters; creating a base of information, guides, and models on the www.irecusa.org and the www.millionsolarroofs.org web sites; convening workshops and seminars; engaging multiple stakeholders; and widening the solar network to include new consumers and decision makers. Two major web sites were maintained throughout the project cycle. The www.irecusa.org web site housed dedicated pages for Connecting to the Grid, Schools Going Solar, Community Outreach, and Certification & Training. The www.millionsolarroofs.org web site was created to serve the MSR Partnerships with news, interviews, key documents, and resource material. Through the course of this grant, the Interstate Renewable Energy Council has been supporting the Department of Energy's solar energy program goals by providing the Department with expertise services for their network of city, state, and community stakeholders. IREC has been the leading force at the state and federal levels regarding net metering and interconnection policy for photovoltaic systems. The principal goal and benefit of the interconnection and net metering work is to lower both barriers and cost for the installation of PV. IREC typically plays a leadership role among small generator stakeholders and has come to be relied upon for its expertise by industry and regulators. IREC also took a leadership

Emerging ternary chalcogenide thin film solar cell technologies, such as CuSbS2 and CuSbSe2, have recently attracted attention as simpler alternatives to quaternary Cu2ZnSnS4 (CZTS). Despite suitable photovoltaic properties, the initial energy conversion efficiency of CuSbS2 is rather low (0.3%). Here, we report on our progress towards improving the efficiency of CuSbS2 solar cells using a high throughput approach. The combinatorial methodology quickly results in baseline solar cell prototypes with 0.6% efficiency, and then modification of the back contact architecture leads to 1% PV devices. We then translate the optimal CuSbS2 synthesis parameters to CuSbSe2 devices, which show 3% efficiencies.

Solarex is developing a manufacturing process for the commercial production of 8 ft{sup 2} multijunction amorphous silicon (a-Si) PV modules starting in 1996. The device structure used in these multijunction modules is: glass/textured tin oxide/p-i-n/p-i-n/ZnO/Al/EVA/Tedlar where the back junction of the tandem structure contains an amorphous silicon germanium alloy. As an interim step, 4 ft{sup 2} multijunction modules have been fabricated in a pilot production mode over the last several months. The distribution of initial conversion efficiencies for an engineering run of 67 modules (4 ft{sup 2}) is shown. Measurements recently performed at NREL indicate that the actual efficiencies are about 5% higher than those shown, and thus exhibit an average initial conversion efficiency of about 9.5%. The data indicates that the process is relatively robust since there were no modules with initial efficiencies less than 7.5%.

This Comprehensive Report encompasses the activities that have been undertaken by Kiss + Cathcart, Architects, in conjunction with Energy Photovoltaics, Incorporated (EPV), to develop a flexible patterning system for thin-film photovoltaic (PV) modules for building applications. There are two basic methods for increasing transparency/light transmission by means of patterning the PV film: widening existing scribe lines, or scribing a second series of lines perpendicular to the first. These methods can yield essentially any degree of light transmission, but both result in visible patterns of light and dark on the panel surface. A third proposed method is to burn a grid of dots through the films, independent of the normal cell scribing. This method has the potential to produce a light-transmitting panel with no visible pattern. Ornamental patterns at larger scales can be created using combinations of these techniques. Kiss + Cathcart, Architects, in conjunction with EPV are currently developing a complementary process for the large-scale lamination of thin-film PVs, which enables building integrated (BIPV) modules to be produced in sizes up to 48 in. x 96 in. Flexible laser patterning will be used for three main purposes, all intended to broaden the appeal of the product to the building sector: To create semitransparent thin-film modules for skylights, and in some applications, for vision glazing.; to create patterns for ornamental effects. This application is similar to fritted glass, which is used for shading, visual screening, graphics, and other purposes; and to allow BIPV modules to be fabricated in various sizes and shapes with maximum control over electrical characteristics.

This document provides a description of the Tank Monitor and Control System (TMACS). It is intended as an introduction for those persons unfamiliar with the system as well as a reference document for the users, maintenance personnel, and system designers. In addition to describing the system, the document outlines the associated drawing documentation, provides maintenance and spare parts information, and discusses other TMACS documents that provide additional detail

This Management Control System (MCS) description describes the processes used to manage the cost and schedule of work performed by Westinghouse Hanford Company (Westinghouse Hanford) for the US Department of Energy, Richland Operations Office (DOE-RL), Richland, Washington. Westinghouse Hanford will maintain and use formal cost and schedule management control systems, as presented in this document, in performing work for the DOE-RL. This MCS description is a controlled document and will be modified or updated as required. This document must be approved by the DOE-RL; thereafter, any significant change will require DOE-RL concurrence. Westinghouse Hanford is the DOE-RL operations and engineering contractor at the Hanford Site. Activities associated with this contract (DE-AC06-87RL10930) include operating existing plant facilities, managing defined projects and programs, and planning future enhancements. This document is designed to comply with Section I-13 of the contract by providing a description of Westinghouse Hanford's cost and schedule control systems used in managing the above activities. 5 refs., 22 figs., 1 tab.

In the U.S., the increasing financial support for customer-sited photovoltaic (PV) systems provided through publicly-funded incentive programs has heightened concerns about the long-term performance of these systems. Given the barriers that customers face to ensuring that their PV systems perform well, and the responsibility that PV incentive programs bear to ensure that public funds are prudently spent, these programs should, and often do, play a critical role in addressing PV system performance. To provide a point of reference for assessing the current state of the art, and to inform program design efforts going forward, we examine the approaches to encouraging PV system performance used by 32 prominent PV incentive programs in the U.S. We identify eight general strategies or groups of related strategies that these programs have used to address factors that affect performance, and describe key implementation details. Based on this review, we then offer recommendations for how PV incentive programs can be effectively designed to mitigate potential performance issues.

Some may say that PV modules are moving toward being a simple commodity, but most major PV customers ask: 'How can I minimize chances of a module recall?' Or, 'How can I quantify the added value of a 'premium' module?' Or, 'How can I assess the value of an old PV system that I'm thinking of purchasing?' These are all questions that PVQAT (the International PV Quality Assurance Task Force) and partner organizations are working to answer. Defining standard methods for ensuring minimal acceptable quality of PV modules, differentiating modules that provide added value in the toughest of environments, and creating a process (e.g. through IECRE [1]) that can follow a PV system from design through installation and operation are tough tasks, but having standard approaches for these will increase confidence, reduce costs, and be a critical foundation of a mature PV industry. This paper summarizes current needs for new tests, some challenges for defining those tests, and some of the key efforts toward development of international standards, emphasizing that meaningful quantification of reliability (as in defining a service life prediction) must be done in the context of a specific product with design parameters defined through a quality management system.

Due to the increasing deployment of PV systems in snowy climates, there is significant interest in a method capable of estimating PV losses resulting from snow coverage that has been verified for a wide variety of system designs and locations. A scattering of independent snow coverage models have been developed over the last 15 years; however, there has been very little effort spent on verifying these models beyond the system design and location on which they were based. Moreover, none of the major PV modeling software products have incorporated any of these models into their workflow. In response to this deficiency, we have integrated the methodology of the snow model developed in the paper by Marion et al. [1] into the National Renewable Energy Laboratory's (NREL) System Advisor Model (SAM). In this work we describe how the snow model is implemented in SAM and discuss our demonstration of the model's effectiveness at reducing error in annual estimations for two PV arrays. Following this, we use this new functionality in conjunction with a long term historical dataset to estimate average snow losses across the United States for a typical PV system design. The open availability of the snow loss estimation capability in SAM to the PV modeling community, coupled with our results of the nation-wide study, will better equip the industry to accurately estimate PV energy production in areas affected by snowfall.

This subcontract report was completed under the auspices of the NREL/SCE High-Penetration Photovoltaic (PV) Integration Project, which is co-funded by the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and the California Solar Initiative (CSI) Research, Development, Demonstration, and Deployment (RD&D) program funded by the California Public Utility Commission (CPUC) and managed by Itron. This project is focused on modeling, quantifying, and mitigating the impacts of large utility-scale PV systems (generally 1-5 MW in size) that are interconnected to the distribution system. This report discusses the concerns utilities have when interconnecting large PV systems that interconnect using PV inverters (a specific application of frequency converters). Additionally, a number of capabilities of PV inverters are described that could be implemented to mitigate the distribution system-level impacts of high-penetration PV integration. Finally, the main issues that need to be addressed to ease the interconnection of large PV systems to the distribution system are presented.

Variability in Photovoltaic (PV) generation resulting from variability in the solar radiation over the PV arrays is a topic of continuing concern for those involved with integrating renewables onto existing electrical grids. The island of Lanai, Hawaii is an extreme example of the challenges that integrators will face due to the fact that it is a small standalone grid. One way to study this problem is to take high-resolution solar measurements in multiple locations and model simultaneous PV production for various sizes at those locations. The National Renewable Energy Laboratory (NREL) collected high-resolution solar data at four locations on the island where proposed PV plants will be deployed in the near future. This data set provides unique insight into how the solar radiation may vary between points that are proximal in distance, but diverse in weather, due to the formation of orographic clouds in the center of the island. Using information about each proposed PV plant size, power output was created at high resolution. The team analyzed this output to understand power production ramps at individual locations and the effects of aggregating the production from all four locations. Hawaii is a unique environment, with extremely variable events occurring on a daily basis. This study provided an excellent opportunity for understanding potential worst-case scenarios for PV ramping. This paper provides an introduction to the datasets that NREL collected over a year and a comprehensive analysis of PV variability in a distributed generation scenario.

In this paper, we analyze the bill savings from PV for residential customers of the California's two largest electric utilities, under existing net metering tariffs as well as under several alternative compensation mechanisms. We find that economic value of PV to the customer is dependent on the structure of the underlying retail electricity rate and can vary quite significantly from one customer to another. In addition, we find that the value of the bill savings from PV generally declines with PV penetration level, as increased PV generation tends to offset lower-priced usage. Customers in our sample from both utilities are significantly better off with net metering than with a feed-in tariff where all PV generation is compensated at long-run avoided generation supply costs. Other compensation schemeswhich allow customers to displace their consumption with PV generation within each hour or each month, and are also based on the avoided costs, yield similar value to the customer as net metering.

The market for grid-connected photovoltaics (PV) in the US has grown dramatically in recent years, driven in large part by PV grant or ''buy-down'' programs in California, New Jersey, and many other states. The recent announcement of a new 11-year, $3.2 billion PV program in California suggests that state policy will continue to drive even faster growth over the next decade. Federal policy has also played a role, primarily by providing commercial PV systems access to tax benefits, including accelerated depreciation (5-year MACRS schedule) and a business energy investment tax credit (ITC). With the signing of the Energy Policy Act of 2005 (EPAct) on August 8, the federal government is poised to play a much more significant future role in supporting both commercial and residential PV systems. Specifically, EPAct increased the federal ITC for commercial PV systems from 10% to 30% of system costs, and also created a new 30% ITC (capped at $2000) for residential solar systems. Both changes went into effect on January 1, 2006, and--absent an extension (for which the solar industry has already begun lobbying)--will last for a period of two years: the new residential ITC will expire, and the 30% commercial ITC will revert back to 10%, on January 1, 2008. How much economic value do these new and expanded federal tax credits really provide to PV system purchasers? And what implications might they hold for state/utility PV grant programs? Using a generic (i.e., non-state-specific) cash flow model, this report explores these questions. We begin with a discussion of the taxability of PV grants and their interaction with federal credits, as this issue significantly affects the analysis that follows. We then calculate the incremental value of EPAct's new and expanded credits for PV systems of different sizes, and owned by different types of entities. We conclude with a discussion of potential implications for purchasers of PV systems, as well as for administrators of state

After 12 to 26 Years of Field Exposure | Department of Energy and Degradation Modes of PV Modules in a Hot Dry Climate: Results After 12 to 26 Years of Field Exposure Failure and Degradation Modes of PV Modules in a Hot Dry Climate: Results After 12 to 26 Years of Field Exposure Presented at the PV Module Reliability Workshop, February 26 - 27 2013, Golden, Colorado pvmrw13_openingsession_asu_mani.pdf (21.07 MB) More Documents & Publications Thermal Cycling Combined with Dynamic

This user's manual describes performance data measured for flat-plate photovoltaic (PV) modules installed in Cocoa, Florida, Eugene, Oregon, and Golden, Colorado. The data include PV module current-voltage curves and associated meteorological data for approximately one-year periods. These publicly available data are intended to facilitate the validation of existing models for predicting the performance of PV modules, and for the development of new and improved models. For comparing different modeling approaches, using these public data will provide transparency and more meaningful comparisons of the relative benefits.

A visual inspection checklist for the evaluation of fielded photovoltaic (PV) modules has been developed to facilitate collection of data describing the field performance of PV modules. The proposed inspection checklist consists of 14 sections, each documenting the appearance or properties of a part of the module. This tool has been evaluated through the inspection of over 60 PV modules produced by more than 20 manufacturers and fielded at two different sites for varying periods of time. Aggregated data from a single data collection tool such as this checklist has the potential to enable longitudinal studies of module condition over time, technology evolution, and field location for the enhancement of module reliability models.

States and Germany | Department of Energy An Analysis of Residential PV System Price Differences between the United States and Germany An Analysis of Residential PV System Price Differences between the United States and Germany Residential photovoltaic (PV) systems were twice as expensive in the United States as in Germany (median of $5.29/W vs. $2.59/W) in 2012. This price discrepancy stems primarily from differences in non-hardware or "soft" costs between the two countries, which

Encapsulant materials used in photovoltaic (PV) modules serve multiple purposes. They physically hold components in place, provide electrical insulation, reduce moisture ingress, optically couple superstrate materials (e.g., glass) to PV cells, protect components from mechanical stress by mechanically de-coupling components via strain relief, and protect materials from corrosion. To do this, encapsulants must adhere well to all surfaces, remain compliant, and transmit light after exposure to temperature, humidity, and UV radiation histories. Here, a brief review of some of the polymeric materials under consideration for PV applications is provided, with an explanation of some of their advantages and disadvantages.

The National Renewable Energy Laboratory/Southern California Edison High-Penetration PV Integration Project is (1) researching the distribution system level impacts of high-penetration photovoltaic (PV) integration, (2) determining mitigation methods to reduce or eliminate those impacts, and (3) seeking to demonstrate these mitigation methods on actual high-penetration PV distribution circuits. This report describes a field demonstration completed during the fall of 2013 on the Fontana, California, study circuit, which includes a total of 4.5 MW of interconnected utility-scale rooftop PV systems. The demonstration included operating a 2-MW PV system at an off-unity power factor that had been determined during previously completed distribution system modeling and PV impact assessment analyses. Data on the distribution circuit and PV system operations were collected during the 2-week demonstration period. This demonstration reinforces the findings of previous laboratory testing that showed that utility-scale PV inverters are capable of operating at off-unity power factor to mitigate PV impacts; however, because of difficulties setting and retaining PV inverter power factor set points during the field demonstration, it was not possible to demonstrate the effectiveness of off-unity power factor operation to mitigate the voltage impacts of high-penetration PV integration. Lessons learned from this field demonstration are presented to inform future field demonstration efforts.

This document provides a description of the baseline system conceptualized for remediating the tank waste stored within the Hanford Site. Remediation of the tank waste will be performed by the Tank Waste Remediation System (TWRS). This baseline system description (BSD) document has been prepared to describe the current planning basis for the TWRS for accomplishing the tank waste remediation functions. The BSD document is not intended to prescribe firm program management strategies for implementing the TWRS. The scope of the TWRS Program includes managing existing facilities, developing technology for new systems; building, testing and operating new facilities; and maintaining the system. The TWRS Program will manage the system used for receiving, safely storing, maintaining, treating, and disposing onsite, or packaging for offsite disposal, all tank waste. The scope of the TWRS Program encompasses existing facilities such as waste storage tanks, evaporators, pipelines, and low-level radioactive waste treatment and disposal facilities. It includes support facilities that comprise the total TWRS infrastructure, including upgrades to existing facilities or equipment and the addition of new facilities.

High up-front costs and a lack of financing options have historically been the primary barriers to the adoption of photovoltaics (PV) in the residential sector. State clean energy funds, which emerged in a number of states from the restructuring of the electricity industry in the mid-to-late 1990s, have for many years attempted to overcome these barriers through PV rebate and, in some cases, loan programs. While these programs (rebate programs in particular) have been popular, the residential PV market in the United States only started to achieve significant scale in the last five years â driven in large part by an initial wave of financial innovation that led to the rise of third-party ownership.

PV customers wish to know how long their PV modules will last, but quantitatively predicting service life is difficult because of the large number of ways that a module can fail, the variability of the use environment, the cost of the testing, and the short product development time, especially when compared with the long desired lifetime. China should play a key role in developing international standards because China manufactures most of the world's PV modules. The presentation will describe the steps that need to be taken to create a service life prediction within the context of a defined bill of materials, process window and use environment. Worldwide standards for cost-effective approaches to service-life predictions will be beneficial to both PV customers and manufacturers since the consequences of premature module failure can be disastrous for both.

This paper reviews the PVUSA power rating method and presents two additional methods that seek to improve this method in terms of model precision and increased seasonal applicability. It presents the results of an evaluation of each method based upon regression analysis of over 12 MW of operating photovoltaic (PV) systems located in a wide variety of climates. These systems include a variety of PV technologies, mounting configurations, and array sizes to ensure the conclusions are applicable to a wide range of PV designs and technologies. The work presented in this paper will be submitted to ASTM for use in the development of a standard test method for certifying the power rating of PV projects.

The U.S. Department of Energy (DOE) SunShot Initiative, in conjunction with the Lawrence Berkeley National Laboratory (LBNL) discusses the installed price of residential PV being significantly lower in Germany than in the United States.

Installations of PV systems have been expanding at a rapid pace in recent years. In the United States, the market for PV is driven by national, state, and local government incentives, including upfront cash rebates, production-based incentives, requirements that electricity suppliers purchase a certain amount of solar energy, and Federal and state tax benefits. These programs are, in part, motivated by the popular appeal of solar energy and by the positive attributes of PV - e.g., modest environmental impacts, avoidance of fuel price risks, coincidence with peak electrical demand, and the location of PV at the point of use. Given the relatively high cost of PV, however, a key goal of these policies is to encourage cost reductions over time. Therefore, as policy incentives have become more significant and as PV deployment has accelerated, so too has the desire to track the installed cost of PV systems over time, by system characteristics, by system location, and by component. A new Lawrence Berkeley National Laboratory report, 'Tracking the Sun: The Installed Cost of Photovoltaics in the U.S. from 1998-2007', helps to fill this need by summarizing trends in the installed cost (i.e., the cost paid by the system owner) of grid-connected PV systems in the U.S. The report is based on an analysis of project-level cost data from nearly 37,000 residential and non-residential PV systems completed from 1998-2007 and installed on the utility-customer-side of the meter. These systems total 363 MW, equal to 76% of all grid-connected PV capacity installed in the U.S. through 2007, representing the most comprehensive data source available on the installed cost of PV in the United States. The data were obtained from administrators of PV incentive programs around the country, who typically collect installed cost data for systems receiving incentives. A total of 16 programs, spanning 12 states, ultimately provided data for the study. Reflecting the broader geographical trends in the

The commercial sector offers strong potential for solar photovoltaics (PV) owing to abundant available roof space suitable for PV and the opportunity to offset the sector's substantial retail electricity purchases. This report evaluated the breakeven price of PV for 15 different building types and various financing options by calculating electricity savings based on detailed rate structures for most U.S. utility territories (representing approximately two thirds of U.S. commercial customers). We find that at current capital costs, an estimated 1/3 of U.S. commercial customers break even in the cash scenario and approximately 2/3 break even in the loan scenario. Variation in retail rates is a stronger driver of breakeven prices than is variation in building load or solar generation profiles. At the building level, variation in the average breakeven price is largely driven by the ability for a PV system to reduce demand charges.

To sustain the commercial success of photovoltaic (PV) technology it is vital to know how power output decreases with time. Unfortunately, it can take years to accurately measure the long-term degradation of new products, but past experience on older products can provide a basis for prediction of degradation rates of new products. An extensive search resulted in more than 2000 reported degradation rates with more than 1100 reported rates that include some or all IV parameters. In this paper we discuss how the details of the degradation data give clues about the degradation mechanisms and how they depend on technology and climate zones as well as how they affect current and voltage differently. The largest contributor to maximum power decline for crystalline Si technologies is short circuit current (or maximum current) degradation and to a lesser degree loss in fill factor. Thin-film technologies are characterized by a much higher contribution from fill factor particularly for humid climates. Crystalline Si technologies in hot & humid climates also display a higher probability to show a mixture of losses (not just short circuit current losses) compared to other climates. The distribution for the module I-V parameters (electrical mismatch) was found to change with field exposure. The distributions not only widened but also developed a tail at the lower end, skewing the distribution.

To sustain the commercial success of photovoltaic (PV) technology it is vital to know how power output decreases with time. Unfortunately, it can take years to accurately measure the long-term degradation of new products, but past experience on older products can provide a basis for prediction of degradation rates of new products. An extensive search resulted in more than 2000 reported degradation rates with more than 1100 reported rates that include some or all IV parameters. In this presentation we discuss how the details of the degradation data give clues about the degradation mechanisms and how they depend on technology and climate zones as well as how they affect current and voltage differently. The largest contributor to maximum power decline for crystalline Si technologies is short circuit current (or maximum current) degradation and to a lesser degree loss in fill factor. Thin-film technologies are characterized by a much higher contribution from fill factor particularly for humid climates. Crystalline Si technologies in hot & humid climates also display a higher probability to show a mixture of losses (not just short circuit current losses) compared to other climates. The distribution for the module I-V parameters (electrical mismatch) was found to change with field exposure. The distributions not only widened but also developed a tail at the lower end, skewing the distribution.

The objective of this project was to reduce the cost of racking for PV solar on flat commercial rooftops. Cost reductions would come from both labor savings and material savings related to the installation process. The rack would need to accommodate the majority of modules available on the market. Cascade Engineering has a long history of converting traditional metal type applications over to plastic. Injection molding of plastics have numerous advantages including selection of resin for the application, placing the material exactly where it is needed, designing in features that will speed up the installation process, and weight reduction of the array. A plastic rack would need to meet the requirements of UL2703, Mounting systems, mounting devices, clamping/retention devices, and ground lugs for use with flat-plate photovoltaic modules and panels. Comparing original data to the end of project racking design, racking material costs were reduced 50% and labor costs reduced 64%. The racking product accommodates all 60 and 72 cell panels on the market, meets UL2703 requirements, contributes only 1.3 pounds per square foot of weight to the array, requires little ballast to secure the array, automatically grounds the module when the module is secured, stacks/nests well for shipping/fewer lifts to the roof, provides integrated wire routing, allows water to drain on the roof, and accommodates various seismic roof connections. Project goals were achieved as noted in the original funding application.

To sustain the commercial success of photovoltaics (PV) it becomes vital to know how power output decreases with time. In order to predict power delivery, degradation rates must be determined accurately. Data filtering, any data treatment assessment of long-term field behavior, is discussed as part of a more comprehensive uncertainty analysis and can be one of the greatest sources of uncertainty in long-term performance studies. Several distinct filtering methods such as outlier removal and inclusion of only sunny days on several different metrics such as PVUSA, performance ratio, DC power to plane-of-array irradiance ratio, uncorrected, and temperature-corrected were examined. PVUSA showed the highest sensitivity while temperature-corrected power over irradiance ratio was found to be the least sensitive to data filtering conditions. Using this ratio it is demonstrated that quantification of degradation rates with a statistical accuracy of +/- 0.2%/year within 4 years of field data is possible on two crystalline silicon and two thin-film systems.